| Photonics, Metamaterials and Physics in Australasia |
14-Dec-2009 |
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| Authors:
Alexander J Glass; GLASS (ALEXANDER J) CONSULTING BERKELEY CA
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 | This report covers the activities in 2009 on an effort to investigate the states of the art within Australasia of research in photonics, metamaterials and physics. Tasks included providing authoritative assessment of progress and opportunities for investment. The focus is on research in Australia, Taiwan, and Japan. |
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| 4th Brigade, 10th Infantry Division Iraqi Army Headquarters Barracks Missan Province, Iraq. Sustainment Assessment |
20-Jul-2009 |
32 pages |
| Authors:
Angelina Johnston; Kevin O'Connor; Todd Criswell; OFFICE OF INSPECTOR GENERAL ARLINGTON VA SPECIAL INSPECTOR GENERAL FOR IRAQ RECONSTRUCTION
|
 | The objective of this project assessment was to provide real-time information on relief and reconstruction projects to interested parties to enable appropriate action to be taken, when warranted. Specifically, the Special Inspector General for Iraq Reconstruction (SIGIR) determined whether the project was operating at the capacity stated in the original contract. To accomplish this, SIGIR determined if the project was at full capability or capacity when accepted by the U.S. ... |
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| Laboratory Characterization of Cor-Tuf Concrete With and Without Steel Fibers |
Jul-2009 |
83 pages |
| Authors:
Erin M Williams; Paul A Reed; Steven S Graham; Todd S Rushing; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS GEOTECHNICAL AND STRUCTURES LAB
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| Personnel of the Geotechnical and Structures Laboratory, U.S. Army Engineer Research and Development Center, conducted a series of laboratory experiments to investigate the strength and constitutive property behavior of baseline ultra-high-performance composite (Cor-Tuf) concrete with and without steel fibers. A total of 23 mechanical property tests were successfully completed for Cor-Tuf1 and Cor-Tuf2 concrete. The mechanical property tests included hydrostatic compression, unconfined compression (UC), triaxial compression (TXC), unconfined direct pull ... |
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| First-Principles Modeling of Mechanics and Chemistry of Materials |
22-Jun-2009 |
9 pages |
| Authors:
Ju Li; OHIO STATE UNIV COLUMBUS DEPT OF MATERIALS SCIENCE AND ENGINEERING
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| Silica (SiO2) glass is one of the essential materials in human civilization for making household items, window panes, lenses and optical fibers. An important reason for its wide adaptation is its formability near the glass-transition temperature (Tg 1100 deg C). Si02 glass at room temperature, however, is usually brittle due to fracture instability. But when the brittle glass is confined in extremely small dimensions at tens of nanometres, the nature ... |
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| Analysis of Shock and High-Rate Data for Ceramics: Equation of State Properties and Fragmentation in the Ballistic Environment |
01-May-2009 |
64 pages |
| Authors:
Dennis E Grady; APPLIED RESEARCH ASSOCIATES INC ALBUQUERQUE NM
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| The project effort reported on here is a continuing study undertaken to collect, survey, analyze and model shock wave, and other related high-rate and supporting data, available for candidate armor ceramics with emphasis on response in the ballistic environment. Ceramics considered here include the various light metal-nonmetal compounds selected by the Army for consideration such as silicon carbide and aluminum oxide, as well as other ceramics, glass ceramics and glasses ... |
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| Through-Thickness Property Measurement of Three-Dimensional Textile Composites |
Apr-2009 |
22 pages |
| Authors:
Paul Moy; Ryan L Karkkainen; Jerome T Tzeng; OAK RIDGE INST FOR SCIENCE AND EDUCATION TN
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| Three-dimensional (3-D) reinforcement of thick composite parts is utilized to increase delamination resistance and through-thickness properties, which often represent the weak link of such structures. Stitching, z-pinning, or a 3-D textile weave may be employed. In the current study of a 3-D, orthogonal-woven, glass-epoxy composite, a specimen is designed for cases in which a sufficiently thick specimen for standard test setups cannot be created due to manufacturing limitations. A minimum ... |
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| An Extensive X-ray Computed Tomography Evaluation of a Fully Penetrated Encapsulated SiC MMC Ballistic Panel |
Apr-2009 |
20 pages |
| Authors:
William H Green; Robert H Carter; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
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| X-ray computed tomography (XCT) is an important nondestructive evaluation technique for revealing the spatial distribution of ballistically induced damage in ceramics. The level of detection and resolution of damage depends on the size of the sample and the parameters of the XCT approach (e.g., focal spot size, magnification, etc.). Previous and ongoing work in this area includes assessment of ballistically induced damage in both individual ceramic targets and ceramic armor ... |
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| Relaxation Behavior of Ca-Based Bulk Metallic Glasses (Preprint) |
Apr-2009 |
29 pages |
| Authors:
Oleg N Senkov; Daniel B Miracle; UES INC DAYTON OH
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| Relaxation behavior of Ca60Mg20Zn20, Ca60Mg20Cu20, Ca65Mg15Zn20, Ca50Mg20Cu30, and Ca55Mg18Zn11Cu16 bulk metallic glasses was determined in the glass transition region using DSC with the heating rates from 1 to 160 K/min. The activation enthalpy of structural relaxation and the fragility index m were found to be smaller in the glassy state (onset of the glass transition) than in the supercooled liquid state (end of glass transition). The Ca-based glass-forming liquids showed ... |
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| Freeze-Spray Deposition of Layered Alumina/Zirconia Composites (Preprint) |
Mar-2009 |
22 pages |
| Authors:
Qiang Fu; Oratai Jongprateep; Ashlee Abbott; Fatih Dogan; MISSOURI UNIV-ROLLA DEPT OF MECHANICAL AND AEROSPACE ENGINEERING
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| A novel freeze-Spray Deposition (FSD) method is described for rapid fabrication of layered composites with controlled layer thickness and uniform microstructure. The graded alumina/zirconia composites are fabricated by freeze-spray deposition of ceramic slurries followed by freeze drying. Aqueous slurries with glycerol addition are sprayed on a cooled substrate using an automated 3-D gantry system. Processing parameters such as viscosity of the ceramic slurries, composition and thickness of deposited layers as ... |
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| Design of Ultra-High Temperature Ceramics for Improved Performance |
28-Feb-2009 |
49 pages |
| Authors:
William G Fahrenholtz; Greg E Hilmas; Jeremy Watts; MISSOURI UNIV OF SCIENCE AND TECHNOLOGY ROLLA
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| The thermal shock behavior and thermal residual stresses were investigated for zirconium diboride-based ultra-high temperature ceramics. The research employed a combined experimental and finite element modeling approach to understand the factors that affected the magnitude and spatial extent of residual stresses. Then, engineered architectures were designed and fabricated to mitigate thermal stresses. This approach led to an improvement in thermal shock behavior. Whereas the strength of conventional SiC particulate reinforced ... |
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| Transient Stress Wave Propagation in One-Dimensional Micropolar Bodies |
Feb-2009 |
22 pages |
| Authors:
C L Randow; G A Gazonas; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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| Certain types of structures and materials, such as engineered multi-scale systems and comminuted zones in failed ceramics, may be modeled using continuum theories incorporating additional kinematic degrees of freedom beyond the scope of classical continuum theories. If such material systems are to be subjected to high strain rate loads, such as those resulting from ballistic impact or blast, it will be necessary to develop models capable of describing transient stress ... |
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| Oxidation of ZrB2 and ZrB2-SiC Ceramics With Tungsten Additions (Preprint) |
Feb-2009 |
11 pages |
| Authors:
S C Zhang; W G Fahrenholtz; G E Hilmas; MISSOURI UNIV-ROLLA DEPT OF MATERIALS SCIENCE AND ENGINEERING
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| The effect of tungsten additions on the oxidation behavior of zirconium diboride-based ceramics was studied. Four mole percent tungsten carbide was added to ZrB2. The oxidation behavior was studied using thermal gravimetric analysis and isothermal testing in flowing air. Upon heating to 1500 degrees C, the mass gain decreased from approx. 14 milligrams/(square centimeter) for nominally pure ZrB2 to approx. 4.5 milligrams/(square centimeter) for tungsten containing ZrB2. After heating to ... |
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| Laboratory Testing of Electro-Osmotic Pulse Technology to Reduce and Maintain Low Moisture Content in Concrete |
Feb-2009 |
33 pages |
| Authors:
Vincent F Hock; Orange S Marshall; Brendan J Danielson; Katherine A Masko; ENGINEER RESEARCH AND DEVELOPMENT CENTER CHAMPAIGN IL CONSTRUCTION ENGINEERING RESEARCH LAB
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| Electro-Osmotic Pulse Technology stops water intrusion through concrete. Water can enter a structure via seepage or through joints and cracks. Electrodes are installed in the concrete and the adjacent soil. A small voltage (up to 30 VDC) is applied between the electrodes producing an electric field across the concrete. The electric field promotes cation, anion, and water molecule movement within the concrete; creates counterflow and associated pressure that opposes seepage; ... |
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| Aqueous Based Freeze-Form Extrusion Fabrication of Alumina Components (Preprint) |
Jan-2009 |
25 pages |
| Authors:
Tieshu Huang; Michael S Mason; Xiyue Zhao; Gregory E Hilmas; Ming C Leu; MISSOURI UNIV-ROLLA DEPT OF MATERIALS SCIENCE AND ENGINEERING
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| Fabricating ceramic materials into complex 3-D components is typically a complicated, costly, and time-consuming process that involves diamond machining to achieve its final shape. In most cases, the initial processing is powder-based, followed by densification (sintering) at elevated temperatures. Only a few circumstances, such as fuse casting and thermal spraying, can ceramics be directly fabricated into near net-shape, fully dense ceramic components. However, these techniques require an extremely high temperature ... |
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| Freeze-Spray Deposition of Layered Alumina/Zirconia Composites (Preprint) |
Jan-2009 |
22 pages |
| Authors:
Qiang Fu; Oratai Jongprateep; Ashlee Abbott; Faith Dogan; MISSOURI UNIV-ROLLA DEPT OF MATERIALS SCIENCE AND ENGINEERING
|
| A novel freeze-Spray Deposition (FSD) method is described for rapid fabrication of layered composites with controlled layer thickness and uniform microstructure. The graded alumina/zirconia composites are fabricated by freeze-spray deposition of ceramic slurries followed by freeze drying. Aqueous slurries with glycerol addition are sprayed on a cooled substrate using an automated 3-D gantry system. Processing parameters such as viscosity of the ceramic slurries, composition and thickness of deposited layers as ... |
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| Analysis of Adhesively Bonded Ceramics Using an Asymmetric Wedge Test |
Dec-2008 |
32 pages |
| Authors:
Robert Jensen; Stephen Koellhoffer; Larry Holmes; Gillespie; Wendy Kosik; Steven McKnight; Andres Bujanda; Craig Copeland; Jessica Dibelka; Aaron Forster; John Jr; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
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| Quantitative determination of adhesive performance when bonding to ceramic substrates has traditionally been a challenge. The brittleness of ceramic materials limits the ability to easily machine these substrates into the specific geometries required for rigorous adhesive fracture energy measurements. In this research, a mixed-mode loading scheme was implemented using an asymmetric wedge test configuration to study the effects of adhesion, promoting surface treatments on fracture energy and bond line durability ... |
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| Nondestructive Evaluation (NDE) of Sintered Silicon Carbide and its Correlation to Microstructure and Mechanical Properties |
Dec-2008 |
9 pages |
| Authors:
Douglas M Slusark; M V Demirbas; Andrew Portune; Steven Miller; Richard A Haber; Raymond Brennan; William Green; Ernest Chin; James Campbell; RUTGERS - THE STATE UNIV PISCATAWAY NJ
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| High density is a critical acceptance criterion for armor ceramics. Quantifying the difference in density between what would be considered to be a good or bad region is complicated. As density is reduced from theoretical, does this infer the presence of defects? The minimum acceptable density that ensures favorable ballistic performance is unknown. This question concerns not only the presence of defective regions, which may include pores or inclusions, but ... |
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| Dynamic Failure Processes Under Confining Stress in AlON, a Transparent Polycrystalline Ceramic |
Dec-2008 |
9 pages |
| Authors:
James W McCauley; B Paliwal; K T Ramesh; Mingwei Chen; SANDIA NATIONAL LABS ALBUQUERQUE NM
|
| An experimental technique is developed to impose a planar lateral confinement in a prismatic specimen (with rectangular cross-section); the setup enabled a controlled and homogeneous stress state with high lateral compressive stresses. A transparent polycrystalline aluminum oxynitride (AlON) specimen was used for the study. The statically pre-compressed specimen was then subjected to axial dynamic compressive loading using a modified compression Kolsky bar setup. Experimental design was performed using 3D computational ... |
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| Using Plasticity Values Determined from Systematic Hardness Indentation Measurements for Predicting Impact Behavior in Structural Ceramics: A New, Simple Screening Technique |
Dec-2008 |
7 pages |
| Authors:
James W McCauley; Trevor E Wilantewicz; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| In general, it has long been known that the hardness of ceramics correlates with gross impact performance, however, not to a degree useful for materials development. Wilkins, Cline and Honodel, 1969, were the first to point out the apparent importance of ceramic plasticity or inelastic deformation mechanisms in BeO and AlN in impact performance. More recently, Lundberg et al., 2000, have made compelling arguments that the compressive yield strength (related ... |
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| New Low-Cost Manufacturing Methods to Produce Silicon Carbide (SiC) for Lightweight Armor Systems |
Dec-2008 |
8 pages |
| Authors:
Ernest Chin; James Campbell; Walter Roy; Jerry LaSalvia; Richard Palicka; Daniel Ashkin; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| Ceramic-based armors, commonly used in personnel protection, are actively being considered for platform vehicles due to their potential to dramatically reduce system weight. Silicon carbide (SiC) has been shown to hold considerable promise as the ceramic component in an armor system, and comes in several grades with differing costs. Hot pressed silicon carbide has been shown to provide excellent ballistic properties, but is manufactured at high cost and in limited ... |
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| Evaluation of Minimum Asphalt Concrete Thickness Criteria |
Oct-2008 |
112 pages |
| Authors:
Haley P Bell; L W Mason; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS GEOTECHNICAL AND STRUCTURES LAB
|
| Personnel of the U.S. Army Engineer Research and Development Center (ERDC) were tasked by Headquarters, Air Combat Command, to evaluate the Department of Defense's (DoD) minimum asphalt concrete thickness criteria outlined in United Facilities Criteria 3-260-02. Recent improvements to the DoD's flexible pavement design procedure and a renewed emphasis on the design and construction of contingency pavements had prompted concerns regarding the design and evaluation of thin asphalt concrete pavements. ... |
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| Experimental and Theoretical Investigation of the High-Pressure Behavior of Concrete |
01-Sep-2008 |
25 pages |
| Authors:
Oana Cazacu; Martin J Schmidt; Mark L Green; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| The results of an experimental study aimed at characterizing the behavior of concrete for high confining pressures (up to 500MPa) are reported. The main characteristics of the response under deviatoric conditions are quasi-linearity in the elastic regime, stress-path dependency, and gradual change from compressibility to dilatancy under increasing deviatoric stress. By performing the cyclic triaxial compression tests with several load-creep-unload and reload cycles, the time influence on the overall behavior ... |
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| Toward Modeling Limited Plasticity in Ceramic Materials |
01-Sep-2008 |
22 pages |
| Authors:
ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
|
| The characteristic features of many armor-related ceramic materials are the anisotropy on the micro-scale level and the very limited, though non-vanishing, plasticity due to limited number of the planes for plastic slip. This work in progress is targeted toward revising phenomenological models of such materials with limited number of slip planes. In order to emphasize the key ideas of our approach, we illustrate the approach using the simplest possible model, ... |
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| Effects of Temperature and Steam Environment on Fatigue Behavior of Three SIC/SIC Ceramic Matrix Composites |
01-Sep-2008 |
229 pages |
| Authors:
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
|
| The fatigue behavior of two woven SiC-SiNC ceramic matrix composites (CMCs) was investigated at 1300 deg C in laboratory air and in steam. The first composite (C1) consists of a PIP SiNC matrix reinforced with Sylramic (Syl) fibers woven in a five-harness satin weave fabric and coated with a proprietary dual-layer interface. The second composite (C2) consists of a modified PIP SiNC matrix reinforced with Sylramic-iBN (Syl-iBN) fibers woven in ... |
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| Creep Behavior of Oxide/Oxide Composites with Monazite Fiber Coating at 1100 deg C in Air and in Steam Environments |
01-Sep-2008 |
425 pages |
| Authors:
Tufan Yeleser; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
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| The creep behavior of six oxide-oxide ceramic-matrix composites (CMCs) was investigated at 1100C in air and in steam. The six CMC systems had an alumina matrix reinforced with Nextel (TradeMark)610 fibers. The CMC systems C1, C2 and C3 were reinforced with 10 uni-directional fiber layers in a symmetric cross-ply orientation while C4, C5,and C6 were reinforced with 8 plies of fiber fabric woven. Composites C2, C3, C4, and C6 had ... |
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| Microstructural Effects on the Corrosion Behavior of Alloys and Ceramics |
30-Jun-2008 |
45 pages |
| Authors:
Todd Allen; Lizhen Tan; NATIONAL ASSOCIATION OF CORROSION ENGINEERS HOUSTON TX
|
| The objective of this research was to investigate the effect of microstructure on the corrosion behavior of metals and ceramics. Representative materials from the important engineering alloys and ceramics were studied to determine their corrosion behavior in supercritical water and during cyclic oxidation in air. The materials included Incoloy alloy 800H, Inconel alloy 617, 12%Cr ferritic-martensitic steel HCM12A, and silicon carbide fabricated by means of chemical vapor deposition (CVD). The ... |
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| SiC Armor Tiles via Magnetic Compaction and Pressureless Sintering |
27-Jan-2008 |
21 pages |
| Authors:
Bhanu Chelluri; Ed A Knoth; L P Franks; IAP RESEARCH INC DAYTON OH
|
| The purpose of the SBIR, entitled "Continuous Dynamic Processing of Ceramic Tiles for Ground Vehicle Protection", was to create a high rate, cost effective manufacturing method for producing silicon carbide (SiC) tiles via a combination of high density Dynamic Magnetic Compaction (DMC) for near net shape green body forming and Pressure-less Sintering (PS) for full density sintered body. |
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| Thermocouple Interactions During Testing of Melt Infiltrated Ceramic Matrix Composites (Postprint) |
Jan-2008 |
12 pages |
| Authors:
R John; G Ojard; G Morscher; Y Gowayed; U Santhosh; J Ahmad; R Miller; PRATT AND WHITNEY AIRCRAFT GROUP EAST HARTFORD CT
|
| As high performance ceramic matrix composite systems, such as Melt Infiltrated (MI) SiC/SiC, are being considered for advanced gas turbine engine applications, the characterization of the material becomes more important. A series of test were conducted where Pt and Ni sheathed Pt thermocouples were used to monitor temperature for short and long duration fast fracture, fatigue and creep tests. While it is known that Si forms eutectics with Pt and ... |
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| Functional Ceramic Ferroelectromagnetic Materials in Single Phase Solid-Solutions |
05 DEC 2007 |
22 pages |
| Authors:
Ratnamala Chatterjee; INDIAN INST OF TECH NEW DELHI CENTRE FOR MATERIALS SCIENCE AND TECHNOLOGY
|
| 1. Perform a detailed study on magneto-dielectric effect in the ferroelectric ferromagnet (FEM) ternary oxide solid solutions like Bi(TM)O3-(La1-xREx)0.67(Ba/Ca)0.33MnO3-BTiO3,where TM=transition metal, initially Fe, RE=Rare Earth and B= Ba, Pb. 2. To find suitable composition such that the ferroelectric and ferromagnetic properties are observable at or near room temperature. 3. To decrease the difference between the ferroelectric (Tfe) and ferromagnetic (TN or Tc) transition temperatures by modifying BiFeO3, and 4. To ... |
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| Dynamic Response and Simulations of Nanoparticle-Enhanced Composites |
15 NOV 2007 |
246 pages |
| Authors:
P. R. Mantena; Ahmed Al-Ostaz; Alexander H. Cheng; MISSISSIPPI UNIV UNIVERSITY MS COMPOSITE STRUCTURES AND NANO ENGINEERING RESEARCH GROUP
|
| Objectives of this research are to characterize the: (a) vibration and acoustic response; (b) low-velocity impact and high-strain energy absorption; (c) effects of freeze-thaw cycling; and (d) molecular dynamics simulations of nanoparticle-enhanced composites and fly- ash based foams that are being considered for the future generation naval structures or retrofitting of existing ones. In this study, the flexural/extensional dynamic modulus, damping, low-velocity impact and high-strain (Hopkinson bar) response of nylon ... |
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| Effect of Interface Structure on the Microstructural Evolution of Ceramics |
06 NOV 2007 |
19 pages |
| Authors:
Wook Jo; Doh-Yeon Kim; Nong-Moon Hwang; SEOUL NATIONAL UNIV (REPUBLIC OF KOREA) SCHOOL OF MATERIALS SCIENCE AND ENGINEERING
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| The interface atomic structure was proposed to have a critical effect on the microstructure evolution during sintering of ceramic materials. In liquid-phase sintering, spherical grains show the normal grain growth behavior without exception, while angular grains often grow abnormally. The coarsening process of spherical grains with a disordered or rough interface atomic structure is diffusion-controlled, because there is little energy barrier for atomic attachments. On the other hand, kink-generating sources ... |
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| Simulation Studies of a Four Component Model of Zr-based Bulk Metallic Glass |
18 OCT 2007 |
14 pages |
| Authors:
Dan Miracle; Peter Harrowell; Julian R. Fernandez; SYDNEY UNIV (AUSTRALIA) SCHOOL OF CHEMISTRY
|
| The objective of the work was to carry out simulation studies on the 5 component Vitreloy-1 metallic glass. This was to include the characterization of interaction potentials and the running of preliminary simulation calculations. One specific goal was to compare the outcomes of these calculations with the prediction of a crystal-based structural approximation to the amorphous state recently proposed by Miracle. To this end, a computational characterization of the Miracle ... |
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| Consolidation of A12O3 Nano-Power by Magnetic Pulsed Compaction and Sintering |
16 OCT 2007 |
13 pages |
| Authors:
Whung W. Kim; KOREA ATOMIC ENERGY RESEARCH INST DAEJEON NUCLEAR MATERIAL TECHNOLOGY DEVELOPMENT TEAM
|
| Successful ulta-fine nano Al2O3 powder was consolidated and sintered using magnetic pulsed compaction. Measurements indicated that many properties in the consolidated Al2O3 bulk have been much improved over the conventional polycrystalline materials. The optimization of the compaction parameters and sintering conditions will lead to the consolidation of Al2O3 nanopowder for the higher density and even further enhanced mechanical properties. |
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| Tensile Creep and Fatigue of Sylramic-iBN Melt-Infiltrated SiC Matrix Composites: Retained Properties, Damage Development, and Failure Mechanisms (Preprint) |
Oct-2007 |
32 pages |
| Authors:
Robert Miller; Reji John; Yasser Gowayed; Gregory N Morscher; Greg Ojard; Unni Santhosh; Jalees Ahmed; PRATT AND WHITNEY EAST HARTFORD CT
|
| The elevated temperature creep, fatigue, rupture, and retained properties of ceramic matrix composites envisioned for use in gas turbine engine applications are essential properties to understand and model for the purposes of component design and life-prediction. In order to quantify the effect of stress, time, temperature, and oxidation for a state-of-the-art composite system: the Sylramic-iBN woven fiberreinforced, BN interphase, melt-infiltrated SiC matrix composite, a wide variety of tensile creep, dwell ... |
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| Unusual Nature of NanoDomains in Ultrahigh Temperature Polymer Derived Ceramics |
25 SEP 2007 |
12 pages |
| Authors:
Rishi Raj; COLORADO UNIV AT BOULDER DEPT OF MECHANICAL ENGINEERING
|
| This grant has the objective of explaining the unusual properties of polymer-derived-ceramics (PDCs), so called because they are made directly from cross-linked polymers by controlled pyrolysis. The PDCs have unusual properties: (i) They remain structurally and chemically stable up to 1500 degrees C, (ii) They are amorphous in Bragg diffraction although small-angle-x ray-scattering shows the presence of nanodomains, (iii) POCs do NOT show steady state creep despite their amorphous structure, ... |
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| Various Ceramics in Multilayer Composite Ground Vehicle Armor |
17 SEP 2007 |
12 pages |
| Authors:
Douglas N. Rose; Elena Bankowski; Mike Clauson; ARMY RESEARCH DEVELOPMENT AND ENGINEERING COMMAND WARREN MI
|
| These briefing charts describe the use of various ceramics in multilayer composite ground vehicle armor. One material that is planned for pilot production is silicon nitride as a material solution for pellets in a pellet armor approach to ground vehicle armor. One of the pilot program's aims is cost reduction, from $200/Kg to $20/Kg. As described in filed patents, armor constructed of assembled ceramic pellets suspended in a matrix binder ... |
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| Cyclic Creep and Recovery Behavior of Nextel(Trademark) 720/Alumina Ceramic Matrix Composite at 1200deg C in Air and in Steam Environments |
SEP 2007 |
164 pages |
| Authors:
Bridgett A. Whiting; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
|
| The cyclic creep and recovery behaviors of the N720/Al2O3 composite were investigated in this research. The ceramic matrix composite (CMC) contains a porous alumina matrix with laminated, woven mullite/alumina (NextelTM 720) fibers. The composite does not have an interface between the fiber and matrix. The CMC relies on the porous nature for flaw tolerance. The objective of this study the influences of monotonic creep and cyclic creep loading histories on ... |
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| Laboratory Characterization of Solid Grade SW Brick |
AUG 2007 |
88 pages |
| Authors:
Erin M. Williams; Stephen A. Akers; Paul A. Reed; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS GEOTECHNICAL AND STRUCTURES LAB
|
| Personnel of the Geotechnical and Structures Laboratory, U.S. Army Engineer Research and Development Center, conducted a laboratory investigation to characterize the strength and constitutive property behavior of solid Grade SW brick. A total of 37 mechanical property tests were successfully completed, consisting of two hydrostatic compression tests, four unconfined compression (UC) tests, 12 triaxial compression tests (TXC), two constant mean normal stress tests, four direct pull (DP) tests, two uniaxial ... |
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| Laboratory Characterization of Gray Masonry Concrete |
AUG 2007 |
99 pages |
| Authors:
Erin M. Williams; Stephen A. Akers; Paul A. Reed; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS GEOTECHNICAL AND STRUCTURES LAB
|
| Personnel of the Geotechnical and Structures Laboratory, U.S. Army Engineer Research and Development Center, conducted a laboratory investigation to characterize the strength and constitutive property behavior of a gray masonry concrete. A total of 38 mechanical property tests were successfully completed: two hydrostatic compression tests, four unconfined compression (UC) tests, 16 triaxial compression (TXC) tests, two uniaxial strain tests, two uniaxial strain load/biaxial strain unload tests, five uniaxial strain load/constant ... |
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| High Temperature Liquid and Glass Precursors for Oxyphosphate Ceramic Composites |
JUL 2007 |
27 pages |
| Authors:
William T. Petuskey; ARIZONA STATE UNIV TEMPE DEPT OF CHEMICAL AND BIOENGINEERING
|
| The overall objective of this project has been explore the structure, dynamics and physical chemistry of rare earth aluminophosphosilicates (REAPS) glasses for the purpose of designing low temperature synthetic routes for fabricating high temperature, high fracture toughness ceramic-matrix-composites. The concept is based on a glass-ceramic approach that combines the densification of glass powders via viscous sintering followed by independent crystallization anneals. The challenge with REAPS glasses is to balance the ... |
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| Analysis of Shock and High-Rate Data for Ceramics: Strength and Failure of Brittle Solids |
JUL 2007 |
48 pages |
| Authors:
Dennis E. Grady; APPLIED RESEARCH ASSOCIATES INC ALBUQUERQUE NM
|
| Ceramics based on composition of the light intermetallic compounds, have demonstrated considerable success as a barrier material in armor applications. The exceptional strength-to-density ratio of ceramic plays a crucial role in the positive performance of ceramics in the terminal ballistic environment. Even the higher density ceramics, such as tungsten based materials, show promising behavior in space-limited armor applications. The implementation, optimization and evaluation of ceramic in armor systems benefit from ... |
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| Extending the Performance of Net Shape Molded Fiber Reinforced Polymer Composite Valves for Use in Internal Combustion Engines |
JUN 2007 |
367 pages |
| Authors:
Richard T. Buckley; COLORADO STATE UNIV FORT COLLINS DEPT OF MECHANICAL ENGINEERING
|
| Fiber Reinforced Composite (FRC) materials offer the possibility of reduced mass and increased performance over metals. Used in internal combustion engines, this may enable increased power and mechanical efficiency. Previous work has both shown structural and thermal limitations. A net-shape resin transfer molded intake valve has been developed, using a single-piece carbon fiber preform and the high temperature polymer PETI-RFI. Performance has been validated through testing. High engine load conditions ... |
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| Evaluation Criteria for Aged Asphalt Concrete Surfaces |
JUN 2007 |
73 pages |
| Authors:
Haley P. Bell; Reed B. Freeman; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS GEOTECHNICAL AND STRUCTURES LAB
|
| An evaluation of aged asphalt concrete (AC) was performed during the period February to December 2006 at the Vicksburg Airport (Vicksburg, MS), Hood Army Airfield and Robert Gray Army Airfield (Fort Hood, TX), Lawson Army Airfield (Fort Benning, GA), Cairns Army Airfield (Fort Rucker, AL), Butts Army Airfield (Fort Carson, CO), and Kandahar Airfield (Kandahar, Afghanistan) to develop a method for predicting the performance of aged AC surfaces in situ. ... |
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| Combinatorial Production and Processing of Oxide Nanopowders for Transparent, Ceramic Lasers |
JUN 2007 |
86 pages |
| Authors:
Richard M. Laine; Stephen C. Rand; MICHIGAN UNIV ANN ARBOR DEPT OF MATERIALS SCIENCE AND ENGINEERING
|
| Since the discovery of transparent polycrystalline alumina by Coble in 1962, transparent and translucent alumina and yttria based ceramics have achieved a significant presence in our everyday lives because of their utility in sodium (and metal halide) vapor lamp envelopes used for example in street lights (automotive lighting). More recently, transparent ceramic scintillators have replaced photographic film in most medical X-ray imaging equipment. Although known for 30 years, transparent ceramic ... |
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| Modeling Damage and Fragmentation in Concrete |
APR 2007 |
22 pages |
| Authors:
John D. Clayton; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
|
| A theory combining nonlinear continuum elasticity, inelasticity, thermodynamics, damage mechanics, and fragmentation is formulated. The model is applied to study concrete subjected to high rate loading as occurs during ballistic impact. Two thermodynamically motivated methods are postulated within this theoretical framework for quantitatively characterizing the mass and velocity distributions of the post-impact debris field, one based upon a local energy balance and a second following global entropy maximization. Here the ... |
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| Effect of Al Addition on Glass Forming Stability of Ca-Mg-Zn-Cu Based Bulk Metallic Glasses (PREPRINT) |
APR 2007 |
21 pages |
| Authors:
O. N. Senkov; J. M. Scott; Daniel B. Miracle; UES INC DAYTON OH
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| The effect of Al addition on glass forming ability and glass stability of Ca-Mg-Zn, Ca-Mg-Cu, and Ca-Mg-Zn-Cu alloys was studied. The glassy alloys were produced by a copper mold casting method as wedge-shaped samples with thicknesses varying from 0.5 mm to 10 mm. Thermal properties, such as the glass transition, crystallization and melting temperatures, as well as heats of crystallization and melting, were determined for the produced glasses. Partial substitution ... |
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| Mechanical Properties of MI SiC/SiC Composites and Their Constituents (Preprint) |
APR 2007 |
22 pages |
| Authors:
Y. Gowayed; G. Ojard; R. Miller; U. Santhosh; J. Ahmad; R. John; AUBURN UNIV AL
|
| A series of 15 melt infiltrated SiC/SiC composites were fabricated per the standard process arrived at by NASA-GRC (01/01 material). This was done based on the in-situ boron nitride process prior to fiber interface coating and subsequent densification. A series of physical property testing was conducted to determine the mechanical properties, cyclic load response, damage progression, and the effect of temperature on elastic properties. Other tests addressed properties that are ... |
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| Requirements Driven UAV Development |
Apr-2007 |
13 pages |
| Authors:
Mark C Patterson; Anthony Brescia; ADVANCED CERAMICS RESEARCH TUCSON AZ
|
| Over the past 5 years Advanced Ceramics Research (ACR) has established itself in the USA as a persistent producer of Tier II class UAVs with 2 gasoline systems in production and 1 electric sonobuoy launched system under development. The Tier II designation as defined by the U.S. Navy and Marine Corps typically refers to a short range tactical UAV with less than 12 hours flight duration and an operational altitude ... |
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| Mode I and Mode II Interlaminar Crack Growth Resistances of Ceramic Matrix Composites at Ambient Temperature |
02 MAR 2007 |
39 pages |
| Authors:
Sung R. Choi; Robert W. Kowalik; Donald J. Alexander; NAVAL AIR WARFARE CENTER AIRCRAFT DIV PATUXENT RIVER MD
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| Interlaminar crack growth resistances were determined for five different SiC fiber-reinforced ceramic matrix composites (CMCs) including three gas-turbine grade melt-infiltrated SiC/SiC composites. Modes I and II crack growth resistances, GI and GII, were evaluated at ambient temperature using double cantilever beam and end notched flexure methods, respectively. The CMCs exhibited GI =200-500 J/m2 and GII=200-900 J/m2. Most of the CMCs, except the SiC/CAS composite, showed rising R-curve behavior either in ... |
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| A Study of Pre-Stress Effect on Dynamic Failure of Transparent Brittle Materials |
MAR 2007 |
19 pages |
| Authors:
G. I. Kanel; S. V. Razorenov; A. S. Savinykh; G. S. Bezruchko; G. V. Garkushin; G. E. Ivanchikhina; RUSSIAN ACADEMY OF SCIENCES MOSCOW INST FOR HIGH ENERGY DENSITIES
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| The report presents results of studying the pre-stress effect on dynamic failure of K8 crown glass, K14 crown glass, fused quartz and sapphire crystals. A technology of radial pre-compression of glass samples has been worked out. Controlled confinement pressure on the specimen in a range of 150 MPa to 550 MPa was provided by installing a shrink-fit metal sleeve on the lateral surface of the glass specimen disk. Results of ... |
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| Thermal Applications for Advanced Metallic Materials (Preprint) |
JAN 2007 |
13 pages |
| Authors:
Jonathan E. Spowart; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
|
| Various applications for advanced metallic materials in the area of thermal management of potential interest to the United States Air Force are discussed. Particular emphasis is given to the following technologies; passive thermal systems utilizing high thermal conductivity metallic composites; lightweight metallic phase-change materials for managing thermal transients; high-efficiency thermoelectric materials for energy harvesting applications. In this paper, a brief background of the current SOA in each technology is presented, ... |
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| Time-Dependent Response of MI SiC/SiC Composites Part 1: Standard Samples (Preprint) |
JAN 2007 |
11 pages |
| Authors:
G. Ojard; R. Miller; Y. Gowayed; J. Chen; U. Santhosh; J. Ahmad; R. John; PRATT AND WHITNEY AIRCRAFT GROUP EAST HARTFORD CT
|
| With the increased interest in using high performance ceramic matrix composites for advanced applications, long-term property behavior is of interest. In this work, time-dependent response of MI SiC/SiC composites (01/01 material) was experimentally evaluated under creep and dwell fatigue loading. A series of standard samples were tested at 815 degrees Celsius and 1204 degrees Celsius at various stress levels and multiple durations. All specimens showed primary and steady state creep ... |
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| Synthesis, Characterization and Properties of Chain Terminated Polyhedral Oligomeric Silsesquioxane-Functionalized Perfluorocyclobutyl Aryl Ether Copolymers (Postprint) |
Jan-2007 |
10 pages |
| Authors:
Joseph M Mabry; Scott T Iacono; Stephen M Budy; Smith; Dennis W Jr; CLEMSON UNIV SC
|
| A new class of perfluorocyclobutyl (PFCB) polymers covalently functionalized with polyhedral oligomeric silsesquioxnes (POSS) is presented. Three discreetly functionalized POSS monomers possessing thermally reactive trifluorovinyl aryl ethers (TFVE) were prepared in good yields. The POSS TFVE monomers were prepared by initial corner capping of cyclopentyl (-C5H9), iso-butyl (-CH2CH(CH3)2), or trifluoropropyl (-CH2CH2CF3) functionalized POSS trisilanols with acetoxyethyltrichlorsilane followed by sequential acid-catalyzed deprotection and coupling with 4-(trifluorovinyloxy)benzoic acid. TFVE functionalized POSS monomers ... |
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| Knowledge Oriented Materials Engineering of Layered Thermal Barrier Systems (NOMELT) |
31 DEC 2006 |
13 pages |
| Authors:
David Srolovitz; Kevin Hemker; Anthony Evans; John Hutchinson; Tresa Pollock; John Smith; PRINCETON UNIV NJ DEPT OF MECHANICAL AND AEROSPACE ENGINEERING
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| A team from academia, Air Force laboratories and industry has been assembled to develop a design code for one of the prevailing failure modes in thermal barrier systems used for aero-turbines. The failure mechanism to be addressed occurs in systems with two-phase bond coats and is manifest as abrupt delamination along the interface between the thermally grown oxide (TGO) and the intermetallic bond coat. The code will integrate several important ... |
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| Seismic Measurement of Concrete Strength Properties |
DEC 2006 |
84 pages |
| Authors:
Haley P. Bell; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS GEOTECHNICAL AND STRUCTURES LAB
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| An assessment of the portable seismic pavement analyzer (PSPA) was conducted during the period February to April 2005 on three military airfields in order to determine the feasibility of rapidly obtaining the modulus and flexural strength of portland cement concrete and asphalt concrete pavements. The PSPA is a nondestructive testing device that measures seismic modulus using ultrasonic surface waves. The objective of this research is to evaluate the PSPA as ... |
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| Local Bonding Arrangements in Amorphous Ge2Sb2Te5: The Importance of GE and TE Bonding |
DEC 2006 |
12 pages |
| Authors:
D. A. Baker; NORTH CAROLINA STATE UNIV AT RALEIGH DEPT OF PHYSICS
|
| Studies of amorphous (a-) semiconductors have been driven by technological advances as well as fundamental theories. Observation of electrical switching, for example, fueled early interest in a-chalcogenides. More recently a-chalcogenides switching has been applied successfully to programmable memory devices, as well as DVD technology where the quest for the discovery of better-suited materials continues. Thus, switching grants researchers today with an active arena of technological as well as fundamental study. ... |
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| Directionally Solidified Multifunctional Ceramics |
DEC 2006 |
17 pages |
| Authors:
Ali Sayir; CASE WESTERN RESERVE UNIV CLEVELAND OH
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| In order to achieve a significant increase in toughening and to retain the toughness at elevated temperatures a new multifunctional approach is proposed. The multifunctionality were achieved through directional solidification of polyphase materials comprising the load-bearing and functional phases. The functional phases include shape recovery and health monitoring. In parallel, new ideas about the load bearing phases were investigated to achieve tougher materials. |
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| Mechanical, Mathematical, and Computer Modeling in Penetration Mechanics - IV (Hybrid Models for Nanostructured Ceramics - II) |
30 NOV 2006 |
65 pages |
| Authors:
Valeriy V. Kartuzov; NATIONAL ACADEMY OF SCIENCES (UKRAINE) FRANTZEVICH INST FOR PROBLEMS IN MATERIALS SCIENCE
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| Penetration of non-deformable projectiles in continuum with various rheological properties has been of interest to researchers for a long time. The first modeling representations of penetration were formulated in XVIII-XIX centuries in Euler's, Poncelet's, Wuich's works, etc. Analysis of these results can be found in A.J. Sagomonjan's monographs. In conjunction with development of more exact and effective technical means in the last two decades, the interest in this problem has ... |
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| Towards Failure Pattern Formation in Brittle Materials |
01-Nov-2006 |
8 pages |
| Authors:
M A Grinfeld; J W McCauley; S E Schoenfeld; T W Wright; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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| Several Edge-on Impact (EOI) tests on transparent glasses and polycrystalline ceramics have shown that failure fronts have an extremely rough morphology, including the appearance of spikes. A simple thermodynamic theory has been used to interpret the observed morphological instability of failure fronts. For the case of isotropic phases, the instability criterion can be obtained in explicit form. |
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| Investigation of Adaptive Control Approaches to Mitigate Shock Impact With Piezoceramics (Armor) |
NOV 2006 |
61 pages |
| Authors:
Marthinus Van Schoor; Jacob Pretorius; MIDE TECHNOLOGY CORP MEDFORD MA
|
| The U.S. Army Research Laboratory sought a Short-Term Analysis Services (STAS) program funded through Army Research Office (ARO) with Mide in the research, design, and development of an adaptive control system to mitigate the shock wave impact on an isolation system during and after a ballistic event. This report documents the initial work performed by Mide. |
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| Off-Axis Creep Behavior of Oxide/Oxide Nextel(Trademark)720/AS-0 (Preprint) |
NOV 2006 |
23 pages |
| Authors:
Dennis J. Buchanan; Reji John; Larry P. Zawada; DAYTON UNIV OH RESEARCH INST
|
| Oxide/Oxide Ceramic Matrix Composites (CMC) are currently being demonstrated in high-temperature aerospace applications where their oxidation resistance is critical to a successful design. Many applications are engine components that are axisymmetric in shape and subject to axisymmetric thermal and mechanical loadings. Traditionally woven CMC materials used in these components are typically made from 0 deg/90 deg fiber architectures. In many cases the highest stresses are not always coincident with the ... |
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| MICROMECHANICS AND MICROSTRUCTURE EVOLUTION: Modeling, Simulation and Experiments. Held in Madrid, Spain on 12-16 September 2005 |
30 OCT 2006 |
|
| Authors:
UNIVERSIDAD POLITECNICA DE MADRID (SPAIN)
|
| The aim of this conference is to bring together scientists who are working on the modeling and simulation of the deformation behavior of materials, and on material microstructural evolution. The focus will be on the interplay between behaviors at different length scales, in particular the atomistic, nano/mesoscales, and continuum aspects necessary to describe the processes that lead to changes in microstructure. Of particular interest are investigations that discuss the bridging ... |
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| Micromechanics and Microstructure Evolution: Modeling, Simulation and Experiments. Conference Held in Madrid, Spain, 12-16 Sep 2005 |
30 OCT 2006 |
95 pages |
| Authors:
UNIVERSIDAD POLITECNICA DE MADRID (SPAIN)
|
| The aim of this conference is to bring together scientists who are working on the modeling and simulation of the deformation behavior of materials and on material microstructural evolution. The focus will be on the interplay between behaviors at different length scales in particular the atomistic nano/mesoscales and continuum aspects necessary to describe the processes that lead to changes in microstructure. Of particular interest are investigations that discuss the bridging ... |
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| Model of High-Energy-Density Battery Based on SiC Schottky Diodes |
OCT 2006 |
20 pages |
| Authors:
Yves Ngu; Marc Litz; Bruce Geil; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
|
| Silicon carbide (SiC) diodes are being investigated as direct energy converters (DECs) for use in small, long-lived nuclear power sources for unattended sensors. Voltage and current measurements on Schottky diodes fabricated from both Si and SiC result in typical efficiencies of 5 to 15%. A drift-diffusion model has been developed to predict the output and to help us better understand the radiation-induced current that results. This report describes the initial ... |
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| Influence of Surface Roughness on The Specular Reflectance of Low Gloss Coatings Using Bidirectional Reflectance Measurements |
OCT 2006 |
70 pages |
| Authors:
Lisa M. Farrier; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
|
| The objective of this study was to determine the effects of surface roughness and incident angle on the reflectance of low gloss coatings at grazing incidence. A specular peak has been identified from the forward scatter at longer wavelengths, 3.39 μm and 10.6 μm, for various painted surfaces. Depending on the surface roughness and wavelength, this specular component occurs at different angles. However, this effect has not been observed in ... |
|
| Special Workshop: Kolsky/Split Hopkinson Pressure Bar Testing of Ceramics |
SEP 2006 |
70 pages |
| Authors:
James W. McCauley; George D. Quinn; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
|
| A special workshop on Kolsky Bar/Split Hopkinson Pressure Bar Testing of Armor Ceramics was held in conjunction with the 29th International Conference and Exposition on Advanced Ceramics and Composites, Cocoa Beach, FL, on 27 January 2005. This special report is a collection of the pertinent information from that workshop. |
|
| Parameter Estimation Versus Homogenization Techniques in Time-Domain Characterization of Composite Dielectrics |
22 AUG 2006 |
29 pages |
| Authors:
H. T. Banks; V. A. Bokil; N. L. Gibson; NORTH CAROLINA STATE UNIV AT RALEIGH CENTER FOR RESEARCH IN SCIENTIFIC COMPUTATION
|
| We compare an inverse problem approach to parameter estimation with homogenization techniques for characterizing the electrical response of composite dielectric materials in the time domain. We first consider an homogenization method, based on the periodic unfolding method, to identify the dielectric response of a complex material with heterogeneous micro-structures which are described by spatially periodic parameters. We also consider electromagnetic interrogation problems for complex materials assuming multiple polarization mechanisms with ... |
|
| 2006 Gordon Research Conference on Ceramics, Solid Studies In |
18 AUG 2006 |
9 pages |
| Authors:
John E. Blendell; Nancy R. Gray; GORDON RESEARCH CONFERENCES INC KINGSTON RI
|
| The Gordon Research Conference (GRC) on CERAMICS, SOLID STATE STUDIES IN was held at Proctor Academy from 8/13/2006 thru 8/18/2006. The Conference was well-attended with 101 participants (attendees list attached). The attendees represented the spectrum of endeavor in this field coming from academia, industry, and government laboratories, both U.S. and foreign scientists, senior researchers, young investigators, and students. In designing the formal speakers program, emphasis was placed on current unpublished ... |
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| Study of Self-Assembly Monolayers for Colloidal Processing of Ceramics and Textured, Super-Hydrophobic |
18 AUG 2006 |
9 pages |
| Authors:
Frederick F. Lange; CALIFORNIA UNIV REGENTS SANTA BARBARA OFFICE OF RESEARCH
|
| Objectives are proposed concerning the molecules that form self assembled monolayers (SAMs) that can be used in colloidal powder processing and the fabrication of textured, super-hydrophobic ceramic surfaces. The first objective is to understand and control the steric forces between particles coated with hydrophilic (water loving) SAMs. This approach is new and will be exploited by industry in a variety of applications. The second is to use this knowledge to ... |
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| Novel SICN Ceramics for Health Monitoring of High Temperature Systems |
14 AUG 2006 |
14 pages |
| Authors:
Rishi Raj; COLORADO UNIV AT BOULDER DEPT OF MECHANICAL ENGINEERING
|
| The objective of this MEANS program was to develop new methodologies for quantifying the variability in the performance of high temperature systems by coupling basic concepts from materials science with system design and engineering. The methodologies were validated by the fabrication and evaluation of new high temperature MEMS devices made from a novel polymer-derived ceramic material. The new results demonstrate two unique features: 1) how to hybridize computational approach with ... |
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| Investigation of a Bulk Metallic Glass as a Shaped Charge Liner Material |
AUG 2006 |
46 pages |
| Authors:
William P. Walters; Laszlo J. Kecskes; Justin E. Pritchett; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| A study was conducted to explore a zirconium-based bulk metallic glass, Vitreloy 106, as a jetting material. In the past, bulk metallic glass alloys (e.g., Vitreloy 106) have been used for other applications such as the binder for kinetic energy penetrators. These alloys are a homogeneous mixture of several metals. Based on the experiments described herein, it was concluded that this zirconium-based bulk metallic glass behaves more like a shaped ... |
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| Low Temperature, Low Pressure Fabrication of Ultra High Temperature Ceramics (UHTCs) |
AUG 2006 |
116 pages |
| Authors:
Yigal Blum; Jochen Marschall; Hans J. Kleebe; SRI INTERNATIONAL MENLO PARK CA
|
| The US Air Force is interested in developing fiber-reinforced ceramic composites that perform at ultra-high temperatures (greater or more than 1500 degrees C) under oxidative conditions, especially for hypersonic vehicles. Two potential approaches are: (a) Utilizing existing carbon-fiber-reinforced carbon-matrix composites (C/C) or carbon-fiber-reinforced silicon carbide-matrix composites (C/SiC) coated by thick (>100 um) ultra-high temperature ceramic (UHTC) coatings, or (b) Replacing the C and SiC matrices of such composites with an ... |
|
| Hybrid Organic-Inorganic Photorefractives (Preprint) |
AUG 2006 |
22 pages |
| Authors:
D. R. Evans; G. Cook; J. L. Carns; M. A. Saleh; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
|
| Surface space charge field modulates the local liquid crystal alignment. Liquid crystals amplify the refractive index modulation. Highlights the opportunity of exploiting the electric field sensitivity and large birefringence of liquid crystals. |
|
| Ceramics that Exhibit a Threshold Strength |
10 JUL 2006 |
12 pages |
| Authors:
Frederick F. Lange; CALIFORNIA UNIV SANTA BARBARA DEPT OF MATERIALS
|
| The strength of a brittle material is not a singular value, but a distributed set of values that reflect the large variety of flaws (types and sizes) that are incorporated during processing. The distribution of strength values obtained during testing of ceramic specimens, all made at one time, are generally characterized by statistical parameters that vary with the processing method and processing period, That is, most manufactures cannot control the ... |
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| Stresses and Crack Extension in Multi-Layered Ceramic Composites |
10 JUL 2006 |
18 pages |
| Authors:
Frederick F. Lange; CALIFORNIA UNIV SANTA BARBARA DEPT OF MATERIALS
|
| It has been demonstrated, through theory and experiments, that compressive layers arrest large surface and internal cracks to produce a stress below which the material will not fail. This enables the materials to have a Threshold Strength. The stress intensity function, K, was derived for a crack sandwiched between two compressive layers. This function suggests that the threshold strength is proportional to the magnitude of the residual, compressive stress, the ... |
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| High Accuracy Multidimensional Parameterized Surrogate Models for Fast Optimization of Microwave Circuits in the Industry Standard Circuit Simulators |
03 JUL 2006 |
53 pages |
| Authors:
Adam Lamecki; Lukasz Balewski; Michal Mrozowski; GDANSK TECHNICAL UNIV (POLAND)
|
| The goal of this project was to advance the techniques for creating multivariate surrogate models of high complexity in order to create full wave models for industry standard circuit simulators (ADS Microwave Office). The models have the accuracy comparable to full wave simulations but at the same time the computational speed similar to the closed form formulae. |
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| Indentation of Bulk Amorphous Metals to Investigate Pop-In Effects |
JUL 2006 |
22 pages |
| Authors:
Tyler Krus; Thomas Juliano; Mark VanLandingham; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
|
| Bulk metallic glasses (BMG) are a fairly new class of materials that exhibit high strength, low density, and corrosive resistance, as compared to traditional metals, and are useful for various applications. Spherical depth-sensing indentation of BMG reveals stepwise displacement jumps in the load-displacement curves, known as pop-ins. These pop-ins have been found to be correlated with plastic deformation; the initial one being associated with the elastic limit of the material. ... |
|
| Freeform Extrusion of High Solids Loading Ceramic Slurries. Part 2. Extrusion Process Control (Preprint) |
JUL 2006 |
13 pages |
| Authors:
Michael S. Mason; Tieshu Huang; Robert G. Landers; Ming C. Leu; Gregory E. Hilmas; MISSOURI UNIV-ROLLA DEPT OF MATERIALS SCIENCE AND ENGINEERING
|
| Part I of this paper provided a detailed description of a novel fabrication machine for high solids loading ceramic slurry extrusion processes and presented an empirical model of the ceramic extrusion process, viewing ram velocity as the input and extrusion force as the output. A constant extrusion force is desirable as it correlates with a constant material deposition rate and, thus, good part quality. The experimental results used to construct ... |
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| Freeform Extrusion of High Solids Loading Ceramic Slurries. Part 1: Extrusion Process Modeling |
JUL 2006 |
16 pages |
| Authors:
Michael S. Mason; Tieshu Huang; Robert G. Landers; Ming C. Leu; Gregory E. Hilmas; MISSOURI UNIV-ROLLA DEPT OF MATERIALS SCIENCE AND ENGINEERING
|
| A novel, solid freeform fabrication method has been developed for the manufacture of ceramic-based components in an environmentally friendly fashion. The method is based on the extrusion of ceramic slurries using water as the binding media. Aluminum oxide (Al2O3) is currently being used as the part material and solids loading as high as 60 vol. % has been achieved. This paper describes a novel manufacturing machine that has been developed ... |
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| Freeze-Form Extrusion Fabrication of Alumina Components Using Aqueous Paste |
JUL 2006 |
22 pages |
| Authors:
Tieshu Huang; Michael S. Mason; Gregory E. Hilmas; Ming C. Leu; MISSOURI UNIV-ROLLA DEPT OF MATERIALS SCIENCE AND ENGINEERING
|
| Freeze-form Extrusion Fabrication (FEF) is an environmentally friendly solid freeform fabrication method that uses aqueous pastes to fabricate ceramic-based components. The process uses only small quantities (2 to 4 vol.%) of organic binder. Using the FEF process, 3-D ceramic components have been fabricated from aluminum oxide (Al2O3) by extrusion deposition of Al2O3 paste in a layer-by-layer manner utilizing a 3-D gantry controlled by a computer using Labview software. Sintered samples ... |
|
| Characterization of Long SiAION Ceramic Tubes for Gun Barrel Applications |
JUN 2006 |
118 pages |
| Authors:
Andrew K. Woodruff; John Hellmann; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF MATERIALS SCIENCE AND ENGINEERING
|
| The extent of density gradients, dimensional fidelity, and strength was examined on several different lots of Kennametal TK4 SiAlON proposed for use as gun-tube liners. The formal U.S. Army Research Laboratory designation for this material is ITK4. Five different tubes of material were received, ITK4-4 (200 mm in length) ITK4-6 (100 mm in length) ITK4-7 (100 in length) IFK4-8 (100 mm in length) and ITK4-14 (200 mm in length). Immersion ... |
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| Effects of Frequency and Environment on Fatigue Behavior of an Oxide-Oxide Ceramic Matrix Composite at 1200 Deg. C |
JUN 2006 |
118 pages |
| Authors:
Griffin Hetrick; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
|
| Advances in aeronautical engineering in the 21st century depend upon materials that can perform well in extreme environments such as high temperatures and oxidizing conditions. Nextel(Trademark)720/Alumina (N720/A) is an oxide/oxide ceramic matrix composite with a porous alumina matrix that has been identified as a candidate material for such applications. This research investigated the effects of frequency on fatigue response of N720/A at 1200C in both air and steam environment. Prior ... |
|
| Effect of Environment on Creep Behavior of an Oxide/Oxide CFCC with 45 deg. Fiber Orientation |
JUN 2006 |
145 pages |
| Authors:
Gregory T. Siegert; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
|
| Aerospace applications require materials capable of maintaining superior mechanical properties while operating at high temperatures and oxidizing environments. Nextel(trademark) 720/A (N720/A), an oxide/oxide ceramic matrix composite (CMC) with a porous alumina matrix was developed specifically to provide improved long-term properties and performance at 1200 deg C. This research evaluated the creep behavior of N720/A with a plus or minus 45 deg fiber orientation at 1200 deg C in: laboratory air, ... |
|
| High-Temperature Testing Fixture for Ceramic O-Rings |
APR 2006 |
18 pages |
| Authors:
David Gray; Robert Kaste; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
|
| A test method is being used to determine the tensile strength of ceramic O-ring specimens as part of an effort at the U.S. Army Research Laboratory to develop ceramic materials for gun barrel applications. The tensile strength of the inner surface of a ceramic O-ring specimen is determined by applying a compressive load at 2 points diametrically opposite each other on the specimen. Testing was conducted at room temperature and ... |
|
| Extending the Season for Concrete Construction and Repair. Phase II - Defining Engineering Parameters |
APR 2006 |
74 pages |
| Authors:
Charles J. Korhonen; ENGINEERING RESEARCH AND DEVELOPMENT CENTER HANOVER NH COLD REGIONS RESEARCH AND ENGINEERING LAB
|
| The Phase I study, conducted prior to the work reported herein, developed the tools to design, mix, place, and cure concrete in cold weather made with various combinations of commercial admixtures. The admixtures helped to protect concrete and maintain productivity, even when the temperature of concrete falls to 5 C soon after mixing. Phase II addressed the effect of high doses of the chemical admixtures studied in Phase I. The ... |
|
| Design of Geopolymeric Materials Based on Nanostructural Characterization and Modeling |
APR 2006 |
68 pages |
| Authors:
G. C. Lukey; J. S. van Deventer; J. L. Provis; P. Duxson; MELBOURNE UNIV (AUSTRALIA) DEPT OF CHEMICAL ENGINEERING
|
| Geopolymers, a class of largely X-ray amorphous aluminosilicate binder materials, have been studied extensively over the past several decades, but largely from an empirical standpoint. The primary aim of this investigation has been to apply a more science-based approach to the study of geopolymers, including introducing a variety of mathematical modelling techniques to the field. Si/Al ordering within the tetrahedral aluminosilicate gel framework is described by a statistical thermodynamic model, ... |
|
| Freeze-Spray Processing of Layered Ceramic Composites (Preprint) |
APR 2006 |
26 pages |
| Authors:
O. Jongprateep; Q. Fu; A> Abbott; F. Dogan; MISSOURI UNIV-ROLLA
|
| Thermal gradients and associated stresses are critical in designing with ceramic composites having low thermal conductivity. In order to reduce the stresses from thermal gradients, compositional gradients are employed in designing of composite structures. This study addresses development of freeze-spray process to fabricate layered ceramic structures with controlled layer thickness and microstructural development. The composites were processed by spraying of ceramic slurries with low binder content and relatively high solids ... |
|
| Creep-Rupture Behavior of a Woven Ceramic Matrix Composite at Elevated Temperatures in a Humid Environment |
MAR 2006 |
118 pages |
| Authors:
Jennifer L. Ryba; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH DEPT OF AERONAUTICS AND ASTRONAUTICS
|
| This study focused on moisture and temperature effects on the embrittlement and stress-rupture life of the SiC/SiC CMC Syl-iBN/BN/SiC. The Syl-iBN/BN/SiC is composed of Sylramic fibers with an in-situ layer of boron nitride (Syl-iBN), boron nitride interphase (BN), and SiC matrix. Stress rupture tests and monotonic tests were performed on the specimens. Tests were conducted under 100% humidity and laboratory air environments at three temperatures, 450 C, 750 C, and ... |
|
| Creep-Rupture and Fatigue Behaviors of Notched Oxide/Oxide Ceramic Matrix Composite at Elevated Temperature |
MAR 2006 |
104 pages |
| Authors:
Mark A. Sullivan; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
|
| Oxide/oxide composites are being considered for use in high temperature aerospace applications where their inherent resistance to oxidation provides for better long life properties at high temperature than most other ceramic matrix composites (CMCs). One promising oxide/oxide CMC is Nextel 720/A (N720/A) which uses an 8-harness satin weave (8HSW) of Nextel 720 fibers embedded in a porous alumina matrix. Possible aerospace applications for N720/A will likely require inserting holes into ... |
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| Low Temperature Reactivities of Ultra-High Temperature Ceramics (Hf-X System) |
MAR 2006 |
11 pages |
| Authors:
Yigal Blum; SRI INTERNATIONAL MENLO PARK CA
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| A growing interest in ultra-high temperature ceramics and their aerospace and turbine applications has led to a renewal of activities to fabricate MB2/SiC composites as the materials of choice, because of their high thermal and oxidation resistance stability. Unfortunately, these composites are currently formed by an expensive, size and shape limited hot-press operation at a temperature range of 1900 to 2200 degrees C. The project investigated chemical reactions at and ... |
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| Characterization of Compressive Creep Behavior of Oxide/Oxide Composite with Monazite Coating at Elevated Temperature |
MAR 2006 |
111 pages |
| Authors:
Patrick R. Jackson; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
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| The compressive creep behavior of a N610/monazite/alumina composite was investigated in this work. The composite consists of a porous alumina matrix reinforced with NextelTM610 fibers coated with monazite in a symmetric cross-ply (0 deg/90 deg/0 deg/90 deg)s orientation. Compressive stress-strain behavior was investigated as well. The addition of monazite coating resulted in ~ 35% loss in compressive strength at 900 deg C and in ~45% loss in compressive strength at ... |
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| Characterization of Functionally Graded Materials |
MAR 2006 |
114 pages |
| Authors:
Benjamin D. Chapman; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH DEPT OF AERONAUTICS AND ASTRONAUTICS
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| The purpose of this study was to characterize the behavior of a functionally graded material through experimentation and analytical modeling. Functionally graded materials are a ceramic metal composite which transitions from metal on one face to ceramic on the opposite face. Creating reliable models required verifying the material properties. This was accomplished through the use of a static modulus of elasticity test as well as a dynamic ping test. The ... |
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| Reactive Processing and Co-Extrusion of Ultra-High Temperature Ceramics and Composites |
28 FEB 2006 |
34 pages |
| Authors:
William G. Fahrenholtz; Gregory E. Himas; Adam L. Chamberlain; James W. Zimmerman; MISSOURI UNIV-ROLLA DEPT OF MATERIALS SCIENCE AND ENGINEERING
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| The processing, properties, and performance of zirconium diboride-ceramics were studied. The initial phase of the work focused on improving the properties of zirconium diboride silicon carbide ceramics prepared from commercial powders by minimizing the-impurity content and controlling the grain size of ceramics prepared by conventional hot pressing. Strengths of more than 1000 MPa (1 GPa) were measured for zirconium diboride containing 20 or-30 volume percent silicon carbide, much higher than ... |
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| Ab-Initio Calculations of Structure and Properties of Nanolaminated MAX Phases |
27 JAN 2006 |
4 pages |
| Authors:
Jochen M. Schneider; RWTH AACHEN UNIV (GERMANY)
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| This report results from a contract tasking RWTH Aachen as follows: A new class of machinable ceramic materials had recently received attention due a unique combination of hardness, toughness, machinability, and oxidation stability. These materials are called MAX phases, where M designates a transition metal, A is mostly a IIIA or IVA element of periodic table, and X stands for C or/and N. MAX phases have a unique nanolaminated atom ... |
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| Scientific Presentations on Superconductivity from 2002-2005 |
JAN 2006 |
393 pages |
| Authors:
Paul N. Barnes; Brandon C. Harrison; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIRECTORATE
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| This program addresses the basic scientific and engineering issues related to the development of the second generation high temperature superconducting (HTS) coated conductor for use in magnet and generator coil windings of power applications relevant to the Air Force (AF). Current work focuses on the development of an ac YBCO coated conductor and enhancement of the current dc coated conductor. The dc coated conductor development is done as part of ... |
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| Computational Design of UHTC Materials for Hypersonic Applications (Preprint) |
JAN 2006 |
28 pages |
| Authors:
Triplicane A. Parthasarathy; R. J. Kerans; S. Chellapilla; A. Roy; UES INC DAYTON OH
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| Ultra-High Temperature Ceramics (UHTC) are attractive candidates for use as leading edge components. This work explores the possibility of using computational methods to design a structure of higher strength and toughness within the constraint of 2D isotropy. The use of low-aspect ratio bone-shaped short fibers (BSSF) to improve fracture toughness and the use of composition tailoring to increase fiber strength were analyzed. Computational models show that significant improvements in fracture ... |
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| Investigation of the Self-Pumped Two-Beam Coupling in a Photorefractive Material Using Beam Propagation Simulation (Preprint) |
JAN 2006 |
12 pages |
| Authors:
D. R. Evans; G. Cook; J. L. Carns; M. A. Saleh; P. P. Banerjee; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH SURVIVABILITY AND SENSOR MATERIALS DIV/HARDENED MATERIALS
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| - At this point we are capable of stimulating the self-pumped contra-directional two-beam coupling in a photorefractive medium with arbitrary shaped beams. - Our simulation shows positive role of the photovoltaic effect in self-pumped contra-directional TBC, in agreement with experimental observation. |
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| Self-Pumped Photorefractive Gratings in Fe:KNbO3 (Preprint) |
JAN 2006 |
16 pages |
| Authors:
Dean R. Evans; G. Gook; J. L. Carns; M. A. Saleh; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH SURVIVABILITY AND SENSOR MATERIALS DIV/HARDENED MATERIALS
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| *High gain confirmed in off-axis geometries for Fe:KNbO3; *Mismatch between theory and experiment for mid-range crystal angles, especially for the a-c plane; *Large apparent variation in the effective trap density with crystal angle; *Modified theory gives a good fit to experimental data; *Mechanism for trap density anisotropy is unclear. |
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| Characterization of Indentation Impressions on Human Enamel for Hardness Measurement |
2006 |
8 pages |
| Authors:
Guangming Zhang; Dung T. Le; Shelly R. Tucker; Stanley J. Ng; MARYLAND UNIV COLLEGE PARK INST FOR SYSTEMS RESEARCH
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| This paper presents results from investigating indentation impressions on human enamel under micro-hardness tests. The experiments of hardness testing were performed on a microhardness indentation machine under different loading conditions. Images of indentation impressions were obtained using an environmental scanning electron microscope. Geometrical shapes of hardness indentations were visualized in three-dimensional space using computer graphics. Quantitative information was obtained through atomic force measurements to characterize "pile-up", "sink-in", and elastic recovery ... |
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| Failure Analysis of High-Power Piezoelectric Transducers |
31 DEC 2005 |
17 pages |
| Authors:
T. B. Gabrielson; PENNSYLVANIA STATE UNIV UNIVERSITY PARK APPLIED RESEARCH LAB
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| Low-frequency projectors for underwater sound are often driven near stress limits because of the conflicting requirements of high power and small size. One common failure mode is ceramic cracking and the associated arcing between high-voltage electrodes. While there are a number of manufacturing defects that can cause premature electric breakdown or premature cracking, a fundamental problem results from the coupling between the electric field and stress in a piezoelectric material. ... |
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| Glass Formability and Diffusion Mechanisms in Bulk Metallic Glasses and Supercooled Liquids |
31 DEC 2005 |
11 pages |
| Authors:
Yue Wu; NORTH CAROLINA UNIV AT CHAPEL HILL
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| Three properties of bulk metallic glasses were investigated: (1) atomic motions; (2) characteristics of bonding and electronic states; (3) fracture. Atomic motion in glassy PdNiCuP was investigated by NMR over a wide temperature range from below the glass transition temperature Tg to above the liquidus temperature Tliq. This study reveals the temperature in the supercooled liquid region, below which motions of different elements begin to diverge. It sheds light on ... |
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| Application of a Brittle Damage Model to Normal Plate-on-Plate Impact |
DEC 2005 |
73 pages |
| Authors:
Martin N. Raftenberg; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
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| A brittle damage model presented by Grinfeld and Wright of the U.S. Army Research Laboratory was implemented in the LS-DYNA finite element code and applied to the simulation of normal plate-on-plate impact. The damage model introduces a state variable measure of damage that evolves in proportion to the elastic strain energy. The model degrades the elastic shear modulus in proportion to the state variable's current level. In a simulation of ... |
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| Micro-Tailoring Multi-Functional Materials for Aerospace Objectives |
DEC 2005 |
21 pages |
| Authors:
Yuri M. Shkel; Robert Rowlands; WISCONSIN UNIV-MADISON BOARD OF REGENTS/RESEARCH SPONSORED PROGRAMS
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| This research demonstrates that both fibers and spherical inclusions in composite can be manipulated by electric or magnetic fields. This capability is applied to micro-tailor microstructure of polymeric composites to meet aerospace design objectives. Composition of graphite, glass, ceramic and metallic constituents dispersed in epoxy are considered. The ultimate goal is to achieve multifunctional performance which is superior to that of conventional composites. This includes controlling local orthotropy, as well ... |
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| "Low"-Temperature Reactivities of Ultra-High Temperature Ceramics (Hf-X System) |
DEC 2005 |
11 pages |
| Authors:
Yigal Blum; Marc Hornbostel; D. B. MacQueen; David Hui; Steve Young; Jochen Marschall; Esperanza Alvarez; Hans-Joachim Kleebe; SRI INTERNATIONAL MENLO PARK CA
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| A growing interest in ultra high temperature ceramics and their aerospace and turbine applications has led to a renewal of activities to fabricate MB2/SiC composites as the materials of choice, because of their high thermal and oxidation resistance stability. Unfortunately, these composites are currently formed by an expensive, size and shape limited hot-press operation at a temperature range of 1900 to 2200 C. The project investigated chemical reactions at and ... |
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| MRS Workshop Explores the Diversity of 3D Multifunctional Ceramic Composites |
DEC 2005 |
3 pages |
| Authors:
Paul V. Braun; ILLINOIS UNIV CHAMPAIGN
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| The MRS Workshop on Three-Dimensional Multifunctional Ceramic Composites was held at the Beckman Institute on the campus of the University of Illinois at Urbana-Champaign (UIUC) October 3-5, 2005. Organized by Paul V. Braun of UIUC, C. Jeffrey Brinker of the University of New Mexico and Sandia National Laboratories, and Shanhui Fan of Stanford University, the workshop reached an audience of about 100 attendees from academic institutions, government laboratories, and private ... |
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| Development of Metal/Ceramic Nanocomposite Powder and Consolidation to Bulk Nanocomposite Components with Retained Nanostructures |
17 NOV 2005 |
13 pages |
| Authors:
Sudipta Seal; Petya Georgieva; Keith Rea; Venkatachalapathy Viswanathan; UNIVERSITY OF CENTRAL FLORIDA ORLANDO DEPT OF MECHANICAL MATERIALS AND AEROSPACE ENGINEERING
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| An instrument innovation has been developed that enables for the minimization of oxidation during Air Plasma Spray (APS). Oxidation is limited due to the creation of a three-part copper shroud that utilizes a custom-fit mounting plate that is affixed to the SG-100 APS plasma gun. Due to the separation of the ambient environment from the plasma flame and the particles traveling through it, this process has been deemed Shrouded Air ... |
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| Novel Deformation Processing of Amorphous MEMS |
26 OCT 2005 |
5 pages |
| Authors:
John J. Lewandowski; CASE WESTERN RESERVE UNIV CLEVELAND OH
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| Novel Deformation processing of amorphous metals has been conducted on a variety of metallic glasses. Both large scale (e.g. 10's mm size) and small scale (e.g. sub-micrometer size) deformation processing has been conducted using some of the unique properties exhibited by metallic glasses. In all cases, the intermediate temperature properties of metallic glasses (e.g. Zr-, Cu-, Fe-, Al-, Hf-based) have been determined using a NIKON-QM2 Hot Microhardness Machine. Once the ... |
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| Highly Damping Hard Coatings for Protection of Titanium Blades |
01 OCT 2005 |
17 pages |
| Authors:
Boris A. Movchan; Anatolii I. Ustinov; UKRAINIAN ACADEMY OF SCIENCES KIEV E O PATON INST OF ELECTRICAL WELDING
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| Sn-Cr-MgO system is used as an example to show the basic capability to produce by EBPVD protective metal-ceramic coatings with a high adhesion strength, high values of hardness and damping capacity on the surface of titanium alloys at substrate temperatures not higher than 400 degrees C. After deposition of such coatings on the surface of titanium samples their endurance limit is preserved. It allows these coatings to be regarded as ... |
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| Transverse Resistivity of YBCO Coated Conductors for AC Use |
OCT 2005 |
42 pages |
| Authors:
Milan Polak; SLOVAK ACADEMY OF SCIENCES BRATISLAVA (SLOVENIA) INST OF ELECTRICAL ENGINEERING
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| This report results from a contract tasking Institute of Electrical Engineering as follows: The Grantee will identify and understand factors affecting the transverse resistivity of filamentary YBCO coated conductors and to study methods to control them, The boundary resistivities of the boundaries between the substrate material (Ni or Ni-alloys) and YBCO as well as between YBCO and the metal layer deposited to stabilize the conductor electromagnetically will be determined, Additional ... |
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| Reactive Conversion of Bioclastic Nanostructures |
28 SEP 2005 |
8 pages |
| Authors:
Kenneth H. Sandhage; GEORGIA INST OF TECH ATLANTA SCHOOL OFMATERIALS SCIENCE AND ENGINEERING
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| Numerous examples can be found in nature of microorganisms that assemble oxide nanoparticles into rigid (bioclastic) microstructures with intricate, but well-controlled 3-D shapes and fine (nanoscale) features. Because such self-assembly is under genetic control, a given microorganism can generate bioclastic replicas with a high degree of fidelity upon biological reproduction. Continuous reproduction (repeated doubling) of such micro-organisms can yield enormous numbers of identically-shaped bioclastic structures. Such genetically-precise and massively-parallel self-assembly ... |
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| Designed Ceramics for Aerospace Applications |
28 SEP 2005 |
7 pages |
| Authors:
I-Wei Chen; PENNSYLVANIA UNIV PHILADELPHIA DEPT OFMATERIALS SCIENCE AND ENGINEERING
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| During this project we have optimized the performance of alpha-SiAlON with respect to the following properties: hardness, fracture toughness, room temperature strength, high temperature strength, oxidation resistance, and machinability. Strong correlations between some of these properties have been found. For example, a positive correlation between fracture toughness and room temperature strength, a positive correlation between high temperature strength and oxidation resistance, a negative correlation between hardness and machinability, and a ... |
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| Mechanisms of Photo Degradation for Layered Silicate-Polycarbonate Nanocomposites |
SEP 2005 |
16 pages |
| Authors:
James M. Sloan; Philip Patterson; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
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| The use of advanced lightweight materials to improve combat survivability has been of crucial interest to the U.S. Army for a number of years. Specifically, hybrid organic/inorganic polymer matrix nanocomposites show promise in providing many of the physical properties required (i.e., lightweight structure, rugged abrasion resistance, and high ballistic impact strength). However, as with any polymer system, these materials are susceptible to degradation over time when exposed to various environmental ... |
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| Analytic Model Development for Ceramic Gun Tubes |
SEP 2005 |
30 pages |
| Authors:
Robert Carter; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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| The equations for calculating the probability of failure for an internally pressurized ceramic tube are straightforward and well defined in the literature. The most common solution is for a tube subjected only to an internal pressure. This approach neglects any external pressure, over wrap, or sheathing system that may be used to maintain or promote a beneficial compressive pre-stress. The current research has focused on the development of a model, ... |
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| Effects of Machining on the Uniaxial and Equibiaxial Flexure Strength of CAP3 AD-995 Al2O3 |
SEP 2005 |
70 pages |
| Authors:
Andrew A. Wereszczak; Jeffrey J. Swab; Reuben H. Kraft; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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| The effect of surface condition on the uniaxial and equibiaxial flexure strength of CoorsTek's CAP3 AD-995 alumina was examined. (Note that this material was found not to be the same as CoorsTek's AD-955 alumina-a comparison and discussion of the differences are provided in this report.) The following four surface conditions were considered: as-fired (i.e., unmachined) surfaces; the condition produced by CoorsTek's standard surface-grinding procedures (i.e., the condition they will provide ... |
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| Failure Fronts in Brittle Materials and Their Morphological Instabilities |
SEP 2005 |
16 pages |
| Authors:
Michael A. Grinfeld; Scott E. Schoenfeld; Tim W. Wright; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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| This report outlines the results of the effort to suggest a theoretical method of describing failure fronts in glasses and ceramics. There are various observations and experiments showing that in addition to standard shock-wave fronts, which propagate with transonic velocities, other much slower wave fronts can propagate within glass or ceramic substances undergoing intensive damage. These moving fronts propagate into intact substance, leaving intensively damaged substance behind them. They have ... |
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| Effects of Environment on Creep Behavior of Two Oxide-Oxide Ceramic Matrix Composites at 1200 degs C |
SEP 2005 |
201 pages |
| Authors:
Pavlos A. Koutsoukos; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
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| Previous studies by the advisor and graduate students examined creep behavior of the Nextel720/Alumina CMC in air and in 100% steam environments at 1200 and 1330 deg C. Results showed that while this oxide/oxide system exhibits an exceptionally high fatigue limit at 1200 deg C it also experiences substantial strain accumulation under sustained loading conditions. Furthermore, these earlier investigations revealed a significant degrading effect of 100% steam environment on material ... |
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| Fabrication and Evaluation of Ceramic Microtubes by Extrusion of Preceramic Polymers |
31 AUG 2005 |
79 pages |
| Authors:
Paolo Colombo; BOLOGNA UNIV (ITALY)
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| This report results from a contract tasking University of Bologna as follows: This work will explore the fabrication of microtubes using commercially available, specialized equipment developed for micro-extrusion of conventional polymers. In this project, preceramic polymers, yielding Si-(O)-(N)-C upon pyrolysis at high temperature, will be used instead of conventional thermoplastic polymers. Microtubes of various diameters will be manufactured using both a single extrusion and a co-extrusion approach. In the latter ... |
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| Dynamic Devitrification of Bulk Metallic Glasses (BMGs) and Composites of BMG With Tungsten |
AUG 2005 |
32 pages |
| Authors:
Laszlo J. Kecskes; Robert H. Woodman; Samuel F. Trevino; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
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| The penetration behavior of tungsten-bulk metallic glass (BMG) matrix composites is expected to be strongly influenced by the deformation behavior of the BMG matrix. It has been hypothesized that when the BMC matrix, initially in its viscous, deeply undercooled state, is subjected to compressive loads under the rapid time scales during ballistic impact, it may become a liquid without devitrification. We have carried out a series of in-situ x-ray diffraction ... |
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| Experimental Determination of Shock Structures in Hetrogeneous Layered Material Systems |
19 JUL 2005 |
267 pages |
| Authors:
Liren Tsai; Vikas Prakash; CASE WESTERN RESERVE UNIV CLEVELAND OH
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| In the present study, in an attempt to better understand the dynamic response of heterogeneous materials, a combined analytical and experimental study is conducted on elastic-elastic and elastic-viscoelastic bilaminates. The analytical approach makes use of the Laplace transform and Floquet theory for ODE with periodic coefficients. The effects of material impedance mismatch, layer density and material inelasticity on shock wave propagation through elastic-elastic and elastic-viscoelastic bilaminates were studied. Besides the ... |
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| Nanograin Ceramic Optical Composite Window |
15 JUL 2005 |
20 pages |
| Authors:
METAMATERIA PARTNERS LLC COLUMBUS OH
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| The principle objective of the Phase I STTR program was to demonstrate the feasibility of producing a dense, transparent nanocomposite material with final grain sizes less than 50 nm. The alumina/zirconia system was initially selected because it has been shown for larger scale systems that immiscible phases are particularly effective in suppressing grain growth. The work was conducted by MetaMateria Partners (MMP) in collaboration with the Particulate Materials Center (PMC) ... |
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| A Hybrid Laser/Aerosol Method for the Synthesis of Porous Nanostructured Calcium Phosphate Materials for Bone Tissue Engineering Applications |
13 JUL 2005 |
6 pages |
| Authors:
Shatoya Brown; Hyunbin Kim; Renato P. Camata; ALABAMA UNIV IN BIRMINGHAM
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| We present a new synthesis method based on laser generation and processing of aerosol particles that can produce calcium phosphate coatings in a porous nanostructured configuration. The process uses laser ablation of crystalline hydroxyapatite targets to produce a calcium phosphate aerosol comprising micro- and nanoparticles that are processed and deposited on metallic substrates under well-controlled temperature and ambient conditions, creating a microporous calcium phosphate network suitable for growth of biogenic ... |
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| Laboratory Characterization of Fine Aggregate Cementitious Material |
JUL 2005 |
101 pages |
| Authors:
Erin M. Williams; Stephen A. Akers; Paul A. Reed; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS GEOTECHNICAL AND STRUCTURES LAB
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| Personnel of the Geotechnical and Structures Laboratory, U.S. Army Engineer Research and Development Center, conducted a laboratory investigation to characterize the strength and constitutive property behavior of a fine aggregate cemented material (FACM). The FACM was designed to have a 34-MPa (5, 000-psi) unconfined strength and to contain no coarse aggregate. Forty-three mechanical property tests two hydrostatic compression tests (HC), four unconfined compression tests (UC), 16 triaxial compression tests (TXC), ... |
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| Dynamic Compressive Responses and Flow Behavior of Damaged Ceramics Under High Confinement |
30 JUN 2005 |
10 pages |
| Authors:
Weinong W. Chen; ARIZONA UNIV TUCSON
|
| We developed a novel dynamic loading/reloading experimental technique modified from a split Hopkinson pressure bar (SHPB) to determine the dynamic properties and to record the damage/failure modes in the ceramic specimen, in which a ceramic specimen was loaded by two consecutive stress pulses. The first pulse determines the dynamic response of the intact ceramic material and then crushes the specimen to a desired damage level. The second pulse then determines ... |
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| Fundamental Structure-Property Relationships for High-Temperature Ceramic Composites |
MAY 2005 |
13 pages |
| Authors:
Elizabeth C. Dickey; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF MATERIALS SCIENCE AND ENGINEERING
|
| This research program focused on studying interface structure and thermal compatibility stresses in several directionally solidified eutectic ceramic materials, which are candidates for high-temperature and ultra-high temperature structural materials in aerospace applications. Under this award we specifically investigated the alumina-zirconia and lanthanum hexaboride-zirconium diboride eutectic systems. High-resolution transmission electron microscopy was utilized to understand interfacial structures in these materials and x-ray diffraction was utilized to measure thermal residual stresses. A ... |
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| Size Effects in Ceramic Materials: Computational Issues Associated with Parameter Estimations |
APR 2005 |
36 pages |
| Authors:
Stephen F. Duffy; Eric H. Baker; CONNECTICUT RESERVE TECHNOLOGIES LLC STOW OH
|
| Two test specimen geometries obtained from circumferentially machined, tubular components have been proposed to investigate different flaw populations that might be present in a ceramic gun barrel. C-ring specimens tested in compression will generate maximum tensile stress states at the outer surface of the barrel. This stress state will activate critical flaws that are oriented parallel to the long axis of the tube. The sectored flexure bar specimen tested in ... |
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| Tensile Stress Rupture Behavior of a Woven Ceramic Matrix Composite in Humid Environments at Intermediate Temperature |
MAR 2005 |
208 pages |
| Authors:
Kevin J. LaRochelle; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
| Stress rupture tests on the Sylramic(TM) fiber with an in-situ layer of boron nitride, boron nitride interphase, and SiC matrix ceramic matrix composite were performed at 550 degrees C and 750 degrees C with 0.0, 0.2, or 0. 6 atm partial pressure of water vapor, pH(sub 2)O. The 550 degrees C, 100-hr strengths were 75%, 65% and 51% of the monotonic room temperature tensile strength, respectively. At 750 degrees C, ... |
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| Effect of Temperature and Steam Environment on Fatigue Behavior of an Oxide-Oxide Continuous Fiber Ceramic Composite |
MAR 2005 |
107 pages |
| Authors:
Chalene A. Eber; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
|
| There is an ever-increasing need for materials that maintain high strength and fracture toughness at elevated temperatures and in complex environments. Advanced aerospace applications are motivating the development of composite materials that can meet demanding requirements. This research effort investigates mechanical behavior of an oxide-oxide continuous fiber ceramic composite (CFCC) consisting of a porous alumina matrix reinforced with mullite/ alumina Nextel 720 fibers developed specifically for advanced aerospace applications. Tension-tension ... |
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| Effect of Hold Times on Fatigue Behavior of NEXTEL (trademark) 720/Alumina Ceramic Matrix Composite at 1200 deg C in Air and in Steam Environment |
MAR 2005 |
106 pages |
| Authors:
John M. Mehrman; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
|
| The aerospace field requires structural materials that can maintain superior mechanical properties while subjected to high temperatures and oxidizing environments. This research investigated the effect of hold times at maximum load on fatigue performance of a Nextel 720/Alumina ceramic matrix composite at 1200 C, explored the influence of environment on material response to cyclic loading with hold times at maximum load, and assessed the effects of loading history on material ... |
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| Mechanical and Thermal Properties of Advanced Ceramics for Gun Barrel Applications |
FEB 2005 |
92 pages |
| Authors:
Jeffrey J. Swab; Andrew A. Wereszczak; Jason Tice; Russ Caspe; Reuben H. Kraft; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
|
| Eight commercially available ceramic materials were procured and evaluated for potential application as gun barrel liners. These materials included an alumina, zirconia, and SiAlON, as well as three silicon carbides and two silicon nitrides. Preliminary evaluation determined the strengths, fracture toughness, Vickers hardness, thermal conductivity, specific heat, and linear coefficient of thermal expansion. An uncensored Weibull analysis was performed on all of the strength data. These databases were developed for ... |
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| Miniature Axisymmetric Streamline Tensile (MAST) Specimen |
19 JAN 2005 |
22 pages |
| Authors:
Paul V. Cavallaro; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| The Navy has a need to test piezoelectric ceramic materials to determine their performance in sonar transducers. Piezoelectric ceramic materials are typically grown as a single crystal, which limits the size of the sample. These materials are very brittle and subject to cracking during use as a transducer. The Navy needs to know the useful life of these materials and the amount of stress that they can be subjected to ... |
|
| Spring 2005 Industry Study. Strategic Materials |
2005 |
48 pages |
| Authors:
Michael Boland; Robert Bromell; Robert Carpenter; Thomas Clark; Thomas Donnelly; Jr. Echernacht Kenneth; David Higgins; Michael Madden; Matthew Martin; Hal Murdock; INDUSTRIAL COLL OF THE ARMED FORCES WASHINGTON DC
|
| Strategic materials are those materials and related technologies whose critical function or availability is essential for US economic competitiveness and security. Emerging materials and innovative technologies are key enablers to military transformation and economic growth. In order to retain its competitive advantage, the US must initiate a comprehensive National Materials Strategy to focus and revitalize the climate for innovation, to develop strategic partnerships for rapid commercialization, and to ensure the ... |
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| Plastic/Brittle Behavior of Consolidated Bodies: Role of Particle Pair Potential |
2005 |
15 pages |
| Authors:
F. F. Lange; CALIFORNIA UNIV REGENTS SANTA BARBARA OFFICE OF RESEARCH
|
| Colloidal powder processing can improve the reliability and strength of ceramics by reducing the size of strength degrading heterogeneities through filtering the powder prior to consolidation. Removing heterogeneities greater than a given size is equivalent to a proof test, namely, truncating the strength distribution. Although significant property improvements can be made with the colloidal approach, new forming methods-consistent with the removal of flaws, are still under development. This development requires ... |
|
| Full Scale Testing of Polymer Reinforced Blast Resistant Windows |
01 DEC 2004 |
69 pages |
| Authors:
Elizabeth Trawinski; Jeff W. Fisher; Robert J. Dinan; AIR FORCE RESEARCH LAB TYNDALL AFB FL MATERIALS AND MANUFACTURING DIRECTORATE
|
| Summary of the state of the art in research and design of protective glazing and recent full-scale testing efforts of the Air Force Research Laboratory (AFRL) on blast resistant windows that use advanced materials. Failure mechanisms observed from recent explosive tests are presented, along with analytical models that are being developed to predict the resistance provided by the polymer reinforcement. Challenges include optimizing mechanical properties of reinforcement, design thickness and ... |
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| Effects of Porosity Distribution on the Dynamic Behavior of Two Varieties of SiC |
DEC 2004 |
52 pages |
| Authors:
Samuel R. Martin; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS TECHNOLOGY DIRECTORATE
|
| In order to understand the microstructural reasons behind variations in ballistic material properties, plate-impact tests were conducted on two sintered silicon carbides with slightly different microstructures. Regular Hexoloy (RH) and Enhanced Hexoloy (EH) were obtained from Saint-Gobain. It was determined that the porosity distribution in EH had fewer large pores leading to an 18% increase in flexural strength over that for RH. Plate-impact experiments were conducted utilizing a VISAR to ... |
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| Degradation and Decontamination of VX in Concrete |
DEC 2004 |
3 pages |
| Authors:
G. W. Wagner; Richard J. O'Connor; Jennifer L. Edwards; Carol A. Brevett; EDGEWOOD CHEMICAL BIOLOGICAL CENTER ABERDEEN PROVING GROUND MD
|
| Reactions of VX in concrete have been studied in situ using solid state 31P NMR. The size of VX drops deposited on concrete affected the natural degradation rate, with 4- L drops reacting faster than 0.2- L drops. The half- life observed for VX on the approximately 1- year-old concrete was on the order of 1 week, significantly faster than the rate observed on much older concrete. Water added to ... |
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| Development Of Very-High-Strength and High-Performance Concrete Materials for Improvement of Barriers Against Blast and Projectile Penetration |
DEC 2004 |
18 pages |
| Authors:
E. F. O'Neill III; T. K. Cummins; B. P. Durst; P. G. Kinnebrew; R. N. Boone; R. X. Torres; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS
|
| The U.S. Department of Defense is constantly pursuing new technologies to improve the capabilities of protective structures in defeating current and emerging threats thus providing a safer environment in which its soldiers must work and fight. Exploiting innovative uses of cement-based materials, the U. S. Army Engineer Research and Development Center (ERDC) is developing several high-performance concretes to mitigate the effects of blast and ballistic threats from conventional and asymmetric ... |
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| Failure Surfaces for the Design of Ceramic-Lined Gun Tubes |
DEC 2004 |
7 pages |
| Authors:
Robert Carter; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| It is desired to incorporate advanced materials in gun barrels to increase service life, enable advanced propellants to provide for increased kinetic energy, and decrease system weight. Ceramic materials possess superior erosion resistance, high temperature performance, and lower density than steel making them attractive candidates as gun tube liners. A new design approach is necessary to address the large variability in strength, one that is probabilistic instead of deterministic in ... |
|
| A Nondestructive Evaluation Technique for Fiber Reinforced Polymer (FRP) Composites Using Acoustic Guided Waves (AGW) |
DEC 2004 |
9 pages |
| Authors:
J. C. Trovillion; V. F. Godinez-Azcuaga; R. D. Finlayson; ENGINEER RESEARCH AND DEVELOPMENT CENTER CHAMPAIGN IL CONSTRUCTION ENGINEERING RESEARCH LAB
|
| In this paper, the predictions of the theoretical model and results obtained in the inspection of FRP wraps on concrete samples with seeded defects are presented. Additionally, the successful use of this NDE technique in the detection and imaging of delaminations, debonds, cracks and steel reinforcement in FRP-Concrete structures are discussed. These results are presented in the form of displayed RF waveforms and color-coded C-scan images. Finally, a description of ... |
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| Hafnium-Based Bulk Metallic Glasses for Kinetic Energy Penetrators |
DEC 2004 |
19 pages |
| Authors:
Laszlo J. Kecskes; Brian T. Edwards; Robert H. Woodman; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| A new family of quinary, hafnium-based, bulk-metallic glass-forming alloys has been developed for use in composite kinetic-energy penetrators. The alloys are based on an invariant point identified in the hafnium copper-nickel ternary system. They are denser than zirconium-based glass-forming compositions, and exhibit a higher reduced glass-transition temperature than alloys prepared by 1:1 hafnium substitution into the zirconium-based alloys. The combination of density and glass-forming ability exhibited by this alloy moves ... |
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| Refractory and Hard Materials in the Ti-Si-B-C-N System - Phase Equilibria, Phase Reactions and Thermal Stabilities |
DEC 2004 |
9 pages |
| Authors:
Hans Juergen Seifert; FLORIDA UNIV GAINESVILLE DEPT OF MATERIALS SCIENCE AND ENGINEERING
|
| A thermodynamic dataset was developed for the quinary Ti-Si-B-C-N system. The phase modeling includes all carbides, nitrides, carbonitrides, borides and silicides which can be used as high temperature structural materials. The CALPHAD approach is used to calculate high-temperature phase reactions in the ternary and quaternary subsystems. The phase stabilities can be derived. All types of phase diagrams, phase fraction diagrams and phase composition diagrams are used to simulate the microstructure ... |
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| Rapid Protein Separations in Microfluidic Devices |
DEC 2004 |
6 pages |
| Authors:
Z. H. Fan; Champak Das; Zheng Xia; Alexander V. Stoyanov; Carl K. Fredrickson; FLORIDA UNIV GAINESVILLE MECHANICAL AND AEROSPACE ENGINEERING
|
| This paper describes fabrication of glass and plastic microfluidic devices for protein separations. Although the long-term goal is to develop a microfluidic device for two-dimensional gel electrophoresis, this paper focuses on the first dimension-isoelectric focusing (IEF). A laser-induced fluorescence (LIF) imaging system has been built for imaging an entire channel in an IEF device. The whole-channel imaging eliminates the need to migrate focused protein bands, which is required if a ... |
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| Ultrashort Pulse Propagation in Negative Index Materials: From Negative Refraction to Nonlinear Pulse Propagation |
DEC 2004 |
3 pages |
| Authors:
Michael Scalora; Mark J. Bloemer; Charles M. Bowden; Giuseppe D'Aguanno; Nadia Mattiucci; TIME DOMAIN CORP HUNTSVILLE AL
|
| Negative index materials (NIMs) hold the promise for super lensing of electromagnetic radiation for applications in radar, THz, and possibly at optical frequencies. We have developed a new vector pulse propagation method that we use to study the electrodynamics of negative index materials (NIMs). Although numerous papers have been published on the unusual properties of NIMs, we are the first to apply a propagation model to the problem. As we ... |
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| Evaporation of Chemical Warfare Agent HD on Glass Surface Under Various Environmental Conditions |
15 NOV 2004 |
51 pages |
| Authors:
Seok H. Hong; Kenneth B. Sumpter; Robert Nickol; Wendel Shuely; EDGEWOOD CHEMICAL BIOLOGICAL CENTER ABERDEEN PROVING GROUND MD
|
| Environmental fate of the chemical warfare agents (CWA) is receiving increasing attention, since the evaluation of the contact or vapor hazard is the critical input for models employed to support decisions to determine the individual as well as collective protection level of the combatants. Once released, CWA might evaporate and be carried by the wind, sorb into the surface material, or both. This can be a function of not only ... |
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| Properties and Improved Space Survivability of POSS (Polyhedral Oligomeric Silsesquioxane) Polyimides |
NOV 2004 |
14 pages |
| Authors:
Sandra J. Tomczak; Darrell Marchant; Steve Svejda; Timothy K. Minton; Amy L. Brunsvold; Eitan Grossman; George C. Schatz; Diego Troya; LiPeng Sun; Irina Gouzman; AIR FORCE RESEARCH LAB EDWARDS AFB CA SPACE AND MISSILE PROPULSION DIV
|
| Kapton polyimide (PI) is widely used on the exterior of spacecraft as a thermal insulator. Atomic oxygen (AO) in lower earth orbit (LEO) causes severe degradation in Kapton resulting in reduced spacecraft lifetimes. One solution is to coat the polymer surface with SiO2 since this coating is known to impart remarkable oxidation resistance. Imperfections in the SiO2 application process and micrometeoroid/debris impact in orbit damage the SiO2 coating, leading to ... |
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| International Conference on Thermal and Environmental Barrier Coatings held at Kloster Irsee, Germany, on 17-22 Aug 2003 |
04 OCT 2004 |
14 pages |
| Authors:
David R. Clarke; CALIFORNIA UNIV SANTA BARBARA DEPT OF MATERIALS
|
| An international conference on "Thermal and Environmental Barrier Coatings" was held at the Swabian Conference Center, Irsee, Germany, under the auspices of Engineering Conferences International and with partial financial support from both the Air Force Office of Scientific Research and the Office of Naval Research. The conference was the first international conference on the subject open to the materials community at large. The conference attracted scientists and engineers from 12 ... |
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| Organic Glasses and Crystals for Miniature Electro-Optic Devices: Synthesis, Characterization, and Applications |
OCT 2004 |
104 pages |
| Authors:
Felix E. Fernandez; Tanja Timofeeva; Sergey S. Sarkisov; PUERTO RICO UNIV MAYAGUEZ
|
| A high-level computational analysis of two-photon absorbing derivatives of piperidone and cyclohexanone was carried out. Obtained data were compared with the experimental results. The molecular cross-section of the two- photon absorption of these compounds, as high as 3000x10(exp -50) cu cm s/photon at nanosecond pumping, makes then promising nonlinear materials for optical limiting in near-infrared region. They also exhibit an intense two-photon exciting fluorescence, of the same order as that ... |
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| Reactive and Nonreactive Binders in Glass/Vinyl Ester Composites |
SEP 2004 |
44 pages |
| Authors:
John C. Brody; John W. Gillespie Jr; DELAWARE UNIV NEWARK CENTER FOR COMPOSITE MATERIALS
|
| This study characterizes and evaluates two types of preform binders reactive thermosets and nonreactive thermoplastics. The interply adhesion between woven glass plies was measured as a function of binder type, concentration, and preforming conditions. It was found that reactive binders offer the potential to provide much larger interply adhesions between glass plies in a preform than thermoplastics and are thus superior choices for the fabrication of complex-shaped preforms requiring little ... |
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| Spall Strength of Silicon Carbide Under Normal and Simultaneous Compression-Shear Shock Wave Loading |
SEP 2004 |
17 pages |
| Authors:
Dattatraya P. Dandekar; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
|
| Spall strength data of sintered and hot-pressed silicon carbide show an initial increase with an increase in the shock-induced stress to around 4 GPa. At impact stress around 6 GPa and above, spall strength data of these materials show a continuous decrease in the magnitude of spall strength. This unusual trend in the spall strength of silicon carbides may be due to the competing roles of (1) localized plasticity, (2) ... |
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| Fuel Cell Support Testing. Delivery Order 0029: Fuel Cells for Aerospace Power |
SEP 2004 |
48 pages |
| Authors:
Binod Kumar; DAYTON UNIV OH RESEARCH INST
|
| The purpose of this effort was the basic advancement of high temperature solid oxide fuel cell electrolyte technology. This paper reports the effects of heterogeneously doped Al2O3 on the ionic conductivity of yttria stabilized zirconia (YSZ). At lower dopant concentration, grain growth occurred and the grain boundaries were re-formed. Subsequent increases in the dopant concentration decreased the transport of oxygen ions. the presence of Al2O3 also leads to a blocking ... |
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| Strength Enhancement and Application Development of Carbon Foam for Thermal Protection Systems |
SEP 2004 |
6 pages |
| Authors:
Christopher Duston; Steve Seghi; Roland Watts; CERAMIC COMPOSITES INC MILLERSVILLE MD
|
| Carbon foam is recognized as having great potential as a component within hybrid (rainbow) Thermal Protection Systems for low angle re-entry vehicles. In this concept, the carbon foam supports a ceramic matrix composite surface by providing selectable insulating or thermally conductive dual-use properties. An initial barrier to implementation was the inherent weakness and friability of the carbon foams. Under a MDA funded SBIR program, Ceramic Composites Inc. has demonstrated the ... |
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| Multifunctional Structural Ceramics with Ferroelastic and Martensitic Transformations |
31 AUG 2004 |
29 pages |
| Authors:
A. Sayir; CASE WESTERN RESERVE UNIV CLEVELAND OH
|
| This program had 2 objectives that were pursued simultaneously. These objectives were: (i) development of process models designed to produce a new family of tough and novel ceramic materials with specific microstructures and (ii) coordinate the findings of the proposed research with the parallel efforts on the material characterization addressed from the atomistic and continuum length scales, where correlations are made between atomic structure and bonding. It was concluded that ... |
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| Implementation of 3D Angular Selective Achromatic Diffraction Optical Grating Device |
10 AUG 2004 |
17 pages |
| Authors:
L. Glebov; V. Smirnov; N. Tabirian; B. Zeldovich; UNIVERSITY OF CENTRAL FLORIDA ORLANDO SCHOOL OF OPTICS/CREOL
|
| Angular Selective Achromatic Diffraction Optical Grating (ASADOG) device has been implemented. Surface reflective grating had 1200 lines per mm. Two identical volume holograms were implemented using Photo-Thermo- Refractive (PTR) glass technology, with spatial frequency 1697 lines per mm. Sequential diffraction of incident light by surface grating by first volume grating and then by second one oriented at 90 degrees resulted in angular selection of incident beam, completely achromatic within the ... |
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| Wave Propagation in a Volume Hologram with Multiple Diffraction Gratings |
10 AUG 2004 |
24 pages |
| Authors:
Steven J. Frederick; FRANCIS MARION UNIV FLORENCE SC
|
| In the last 10 years, Bragg diffraction gratings have been developed at CREOL using photo-thermo-refractive (PTR) glass, which is not sensitive to radiation or temperatures to 400 degrees C, and can withstand high-intensity laser beams without damage or change in the Bragg angle. In this work, a new type of Bragg grating, not yet fabricated, is being studied to predict its properties. It is composed of two gratings in the ... |
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| Efficient Local Packing in Metallic Glasses |
AUG 2004 |
11 pages |
| Authors:
D. B. Miracle; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
|
| A simple topological model in an earlier manuscript has shown that efficient atomic packing is a fundamental principle in the formation of metallic glasses. An approach for defining and quantifying the local packing efficiency, P. was developed for solute-centered clusters that contained only solvent atoms in the first coordination shell. In the present research. this methodology is extended to allow quantification of P when more than one atomic species is ... |
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| Fundamentals of Friction and Vapor Phase Lubrication |
30 JUL 2004 |
14 pages |
| Authors:
Andrew J. Gellman; CARNEGIE-MELLON UNIV PITTSBURGH PA DEPT OF CHEMICAL ENGINEERING
|
| This is the final report for the three year research program on "Fundamentals of Friction and Vapor Phase Lubrication" conducted at Carnegie Mellon with support from AFOSR grant number F49630-01-1-0069. The report summarizes the program objectives and summarizes the accomplishments and progress of the research towards the development of new methods for high temperature, vapor phase lubrication (VPL), understanding the tribological properties of quasicrystalline films and the development of a ... |
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| Numerical Modeling of Penetration Into a Compressible Viscoplastic Media |
22 JUL 2004 |
20 pages |
| Authors:
Ioan R. Ionescu; UNIVERSITE DE SAVOIE LE BOURGET-DU-LAC (FRANCE)
|
| This report results from a contract tasking Universite de Savole as follows: The contractor will develop new computational techniques and use them to gain fundamental understanding of the physical phenomena associated with penetration into a semi-infinite geological target of a hard (rigid) penetrator at intermediate impact velocities (typically below 1000 m/s). The contractor we will implement viscoplastic models accounting for the combined effects of high strain rate and high confinement ... |
|
| High Temperature Studies of La-Monazite |
JUL 2004 |
103 pages |
| Authors:
David Marshall; Janet B. Davis; ROCKWELL SCIENTIFIC CO THOUSAND OAKS CA
|
| This report summarizes results from a 3-year research effort aimed at gaining a basic understanding of high-temperature properties of LaP04, with a view to its application in high-temperature structural composites. Previous studies at Rockwell and the Air Force established that LaP04 has a unique set of properties that make it suitable as a weakly bonded interphase material that enables damage tolerance by decoupling damage in the matrix and the reinforcing ... |
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| Hybrid Fiber Sizings for Enhanced Energy Absorption in Glass-Reinforced Composites |
JUL 2004 |
45 pages |
| Authors:
Robert E. Jensen; Steven H. McKnight; Dave P. Flanagan; Alan R. Teets; Donovan Harris; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| Achieving high-impact energy absorption without loss of structural performance in a glass fiber-reinforced composite can be obtained through a materials by design approach of the fiber matrix interphase through modification of current commercially formulated silane-based fiber-sizing packages. In this report, we document the structural and impact performance of composites produced using a fiber-sizing package designed to provide strong fiber-matrix bonding at low-impact rates and weak fiber-matrix bonding at high-impact rates. ... |
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| Solid Bonded Films or Monolithic Ceramics in Tracked Chains of Construction Equipments for Wear Management |
01 JUN 2004 |
21 pages |
| Authors:
M. Ketting; F. Tintrup; H. Halama; J. Tomaszewski; M. Woydt; IBAF GMBH BOCHUM (GERMANY)
|
| Unlubricated tracked chains were realized using soft solid bonded films for the inner wear of the tribosystem of bushing/pin and monolithic ceramic bushings for the outer wear of the tribosystem bushing/sprocket. Both novel approaches were tested on D6 22-to. dozers. Selected solid bonded films and specific monolithic ceramics, offer a potential for simplifying the design, reducing weight and designing a dry-running longlife chain. These results can be further transferred to ... |
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| Replacement Alternatives to the Chromate Wash Primer DOD-P-15328D |
JUN 2004 |
26 pages |
| Authors:
Pauline Smith; Kestutis Chesonis; Christopher Miller; John Escarsega; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| The major advantage of the Department of Defense (DOD)-P-15328DD1 wash primer is to enhance corrosion resistance through the passivation of the metal surface. In the U.S. Army's Chemical Agent Resistant Coating (CARC) system, the wash primer DOD-P-15328D is overcoated with an epoxy primer and followed by a camouflage urethane topcoat. Several coating procedures specify the use of the wash primer, DOD-P-15328D, as a surface treatment prior to the application of ... |
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| The Effect of Hot Isostastic Pressing on the Optical Properties Of Spinel |
20 MAY 2004 |
18 pages |
| Authors:
Gary Gilde; Parimal Patel; Philip Patterson; David Blodgett; Donald Duncan; Daniel Hahn; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| The effect of different hot isostatic pressing (HIP) temperatures and pressures on the optical transmission of hot pressed spinel was studied. The transmittance and extinction coefficient were measured. The transmittance data was used to determine the relative size of the scattering sites. HIP temperatures as low as 1500 degree C were seen to be effective in increasing the transmittance. The transmittance increased with increasing HIP temperature and pressure. The size ... |
|
| A Century of Sapphire Crystal Growth |
17 MAY 2004 |
74 pages |
| Authors:
Daniel C. Harris; NAVAL AIR SYSTEMS COMMAND CHINA LAKE CA
|
| In Paris around 1890, A. V. L. Verneuil developed a flame fusion process to produce ruby and sapphire. By 1900 there was brisk demand for ruby manufactured by Verneuil's method, which was used with little alteration for 50 years. From 1932-1953, S. K. Popov in the Soviet Union established a capability for manufacturing high quality sapphire by the Verneuil process. In the U.S., under government contract during World War II, ... |
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| PTR Glass Melting Facility for Fabrication of Diffractive Optical Elements |
15 MAY 2004 |
18 pages |
| Authors:
Leonid Glebov; UNIVERSITY OF CENTRAL FLORIDA ORLANDO SCHOOL OF OPTICS/CREOL
|
| The proposed research instrumentation, a Photo-Thermo-Refractive (PTR) Glass Melting Facility, is used to support MDA-funded and new research initiatives in the study of photosensitive glass for rugged volume diffractive optical elements. This instrumentation significantly impacts existing efforts in hologram recording in PTR glasses. Diffractive optical elements made from this glass are used in the BMDO/MDA-funded program "Holographic Narrow-Band Filter and Data Storage for Optical Target Characterization" and a number of ... |
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| Design and Analysis of a 15-kV Package for Wide Bandgap Semiconductor |
MAY 2004 |
18 pages |
| Authors:
Dimeji Ibitayo; C. W. Tipton; ARMY RESEARCH LAB ADELPHI MD
|
| The development of wide bandgap semiconductor materials such as silicon carbide (SiC) has made possible devices that exceed the voltage ratings of conventional component packaging schemes. As such a new class of high voltage packages must be developed to realize the full potential of these technologies. We report on the electrostatic analysis and design of a t5-kV ceramic package using the ANSYS Multiphysics software. To baseline our work. a standard ... |
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| Laser Heated Gradient NMR Studies of Ceramic Liquids |
MAY 2004 |
8 pages |
| Authors:
R. F. Marzke; G. H. Wolf; ARIZONA STATE UNIV TEMPE DEPT OF PHYSICS
|
| We report progress in two areas of research on NMR of ceramic liquids: the synthesis and characterization of new materials along La-monazite - alumina/CaO joins, and the 27Al NMR measurement of incoherent Al motions in aluminum-containing ceramic melts. The addition of La-monazite to molten alumina or to molten C12A7 produces an increase in tetrahedral bonding in the liquid, as evidenced by the change of 27Al chemical shift to higher 4-fold ... |
|
| Tb and Ce Doped Y123 Films Processed by Pulsed Laser Deposition |
MAY 2004 |
6 pages |
| Authors:
Joseph W. Kell; Timothy J. Haugan; Mary Frances Locke; Paul N. Barnes; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIRECTORATE
|
| To evaluate possible flux pinning enhancement in YBa2Cu3O7(7-x)(Y123) films due to partial rare-earth ion substitutions, Ce and Tb doping are studied. Bulk ceramic targets of varying compositions (Y(1-x)RE(x)Ba2Cu3O7(7-x) were made with several doping levels (x = 0.001 to 0.1, RE = Ce or Tb) by using regular solid-state reaction and sintering procedures. These targets were used to deposit Ce and Tb doped YBCO films onto SrTiO3 single crystal substrates by ... |
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| Flux Pinning and Properties of Solid-Solution (Y,Nd)1+XBa2-x Cu3O7-delta Superconductors Processed in Air and Partial Oxygen Atmospheres (Preprint) |
APR 2004 |
8 pages |
| Authors:
T. J. Haugan; J. M. Evans; J. C. Tolliver; I. Maartense; P. N. Barnes; W. Wong-Ng; L. P. Cook; R. D. Shull; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIRECTORATE
|
| The effect of chemical composition substitutions on the flux pinning and physical properties of (Y,Nd) 1 + (XB(alpha2)-xCu3O7(-gamma)) superconductors was studied in powders processed by solid-state reaction and equilibrated in air at 910 deg C. The powders were subsequently processed in 1% O2 atmosphere at |
|
| Effect of Sc and Heat Treatment on Microstructure and Properties of a 7XXX DC Cast Alloy |
01 MAR 2004 |
|
| Authors:
O. N. Senkov; R. B. Bhat; S. V. Senkova; J. Tatalovich; AEROJET SACRAMENTO CA
|
| Four developmental 7XXX series alloys modified with Sc, Zr and other dispersoid-forming elements were produced by continuous direct chill (DC) casting. Microstructure and mechanical properties were evaluated in both the longitudinal and transverse directions at room and cryogenic temperatures. The homogenization, solution treatment and aging schedules were optimized to obtain superior mechanical properties. In particular, the Sccontaining cast alloys showed tensile properties similar or even superior to the properties of ... |
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| Directionally Solidified Eutectic Ceramics; In-Situ Composites for High Temperature Structural Applications |
25 FEB 2004 |
111 pages |
| Authors:
Ali Sayir; CASE WESTERN RESERVE UNIV CLEVELAND OHDEPT OF MATERIALS SCIENCE AND ENGINEERING
|
| Eutectics are multiphase structures formed by the cooperative growth of two or more phases. Although the internal structure can vary widely, the development of continuous rods or plates in a matrix can be achieved and, within limits, can be controlled or "tailored" through directional solidification. The eutectic architecture of a continuous reinforcing phase within a higher volume phase or matrix, can be described as a naturally occurring in-situ composite. In-situ ... |
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| Photo-Stereo Lithography System for Polymer Derived Ceramic Microsystems |
20 FEB 2004 |
16 pages |
| Authors:
Rishi Raj; COLORADO UNIV AT BOULDER DEPT OF MECHANICAL ENGINEERING
|
| A photo-stereolithography system, Viper s12, sold by the company 3D Systems, as described in the original proposal, was acquired in the summer of 2003. The system was delivered and installed by the vendor in June 2003. A graduate student, Tsali Cross, and a post-doctoral associate, Neil Cramer, from the College of Engineering at the University of Colorado received intensive training at the company site in California during Fall 2003. Since ... |
|
| Prediction of the Formulation Dependence of the Glass Transition Temperature for Amine-Epoxy Copolymers Using a Quantitative Structure-Property Relationship Based on the AM1 Method |
FEB 2004 |
30 pages |
| Authors:
Jason A. Morrill; Robert E. Jensen; Phillip H. Madison; Cary F. Chabalowski; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| A designer Quantitative Structure-Property Relationsbip (QSPR) based upon molecular properties calculated using the AM1 semi-empirical quantum mechanical metbod was developed to predict the glass transition temperature (Tg) of an%ine-cured epoxy resins based on tbe diglycidyl etber of bisphenol A. The QSPR (R2 - 0.9977) was generated using the regression analysis progran% Con%prebensive Descriptors for Structural and Statistical Analysis (CODESSA). By applying an ad hoc treatn%ent based on elen%entary probability fl%eory ... |
|
| Lightweight, Robust and Low Cost Carbide/Tungsten Composites in Near Net Shapes for Advanced Solid-Fueled Rocket Nozzles for the IHPRPT Program |
FEB 2004 |
64 pages |
| Authors:
Ken H. Sandhage; GEORGIA INST OF TECH ATLANTA SCHOOL OFMATERIALS SCIENCE AND ENGINEERING
|
| The DCP process has been used to synthesize very-high-melting, lightweight tungsten/carbide or tungsten/boride composites via conversion reactions of the following type: (M) + WX(s) = MX(s) + W(s) (1) where (M) is a reactive element dissolved within a Cu-bearing melt, and WX and MX are ceramic reactant and product phases, respectively. Reactions leading to ZrC/W, TiC/W, HfC/W, and ZrB2/W composites at <1300 deg C have been demonstrated. Conversion reactions leading ... |
|
| Genetically-Engineered Microdevices |
FEB 2004 |
16 pages |
| Authors:
Ken H. Sandhage; GEORGIA INST OF TECH ATLANTA SCHOOL OFMATERIALS SCIENCE AND ENGINEERING
|
| Gas/solid displacement reactions have been examined as a means of altering the chemistry of bioclastic silica structures (e.g., the self-assembled microshells of diatoms, a type of aquatic algae) into other ceramic compositions. Complex-shaped silica microshells with nanoscale features were exposed to Mg(g) at <9OO deg C. The silica microshells underwent the following net displacement reaction: 2Mg(g) + SiO2(s) yields 2MgO(s) + ?Si) (1) where ?Si! refers to silicon dissolved within ... |
|
| Selection of a Material Model for Simulating Concrete Masonry Walls Subjected to Blast |
FEB 2004 |
147 pages |
| Authors:
James S. Davidson; Lee Moradi; Robert J. Dinan; ALABAMA UNIV IN BIRMINGHAM
|
| One of the most common methods of construction is the use of concrete masonry units (CMU) in the walls of buildings. However, they are vulnerable to blast, and result in collapse, fragmentation, and severe injury to occupants. An understanding of the behavior of CMU walls during blast is key to developing mitigation techniques. Research has been conducted using the finite element method to simulate structural failure due to blast. A ... |
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| Injectable Ceramic Microcast Silicon Carbonitride (SiCN) microelectromechanical System (MEMS) for Extreme Temperature Environments with Extension: Micro Packages for Nano-Devices |
JAN 2004 |
134 pages |
| Authors:
Victor M. Bright; Rishi Raj; Martin L. Dunn; John W. Daily; COLORADO UNIV AT BOULDER OFFICE OF CONTRACTS AND GRANTS
|
| MEMS that can survive ultrahigh-temperatures and corrosive environments are important in a variety of unique applications. This work develops an innovative microfabrication technology for high temperature MEMS: microcasting of injectable polymer-derived SiCN ceramic materials. The techniques allow realization of MEMS with complex, three-dimensional and multilayer geometry useable to 1500 C. Our approach is easy and low cost. Several MEMS were realized and evaluated. The objectives of the extension research project ... |
|
| Multifunctional Hybrid Carbon Foams: Processing, Characterization and Modeling |
2004 |
7 pages |
| Authors:
Ozden O. Ochoa; M. D. Sarzynski; K. Lafdi; TEXAS A AND M UNIV COLLEGE STATION DEPT OF MECHANICAL ENGINEERING
|
| Carbon and ceramic foams are at the center of intensive development for thermal management, thermal protection, filtration, packing, sensor and structural applications 1,2. The objective of this research is to develop and characterize multi-functional foams with optimal thermal, electrical, magnetic and oxidation resistant properties. |
|
| Near Net-Shape, Ultra-High Melting, Recession-Resistant ZrC/W-Based Rocket Nozzle Liners via the Displacive Compensation of Porosity (DCP) Method (POSTPRINT) |
2004 |
12 pages |
| Authors:
M. B. Dickerson; P .J. Wurm; J. R. Schorr; W. P. Hoffman; P. G. Wapner; K. H. Sandhage; GEORGIA INST OF TECH ATLANTA SCHOOL OF MATERIALS SCIENCE AND ENGINEERING
|
| Dense, near net-shaped ZrC/W-based composites have been fabricated at modest temperatures and at ambient pressure by a reactive infiltration process known as the Displacive Compensation of Porosity (DCP) method. Porous WC preforms with hourglass shapes (for rocket nozzle liners) were produced by gel casting, whereas simple bar-shaped preforms were produced by uniaxial pressing. The porous preforms were exposed to molten Zr2Cu at 1200-1300 deg C and ambient pressure. The Zr2Cu ... |
|
| Structure-Forming Principles for Amorphous Metals |
2004 |
|
| Authors:
D. B. Miracle; O. N. Senkov; W. S. Sanders; K. L. Kendig; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
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| The purpose of this research is to establish structure forming principles that govern the atomic structures of metallic glasses. A structural model based on efficient atomic packing will be discussed and applied to the topological systems that represent most metallic glass alloys. The concept of efficient atomic packing has direct and specific implications regarding the local structure and composition of metallic glasses. Specific solute-to-solvent atomic radius ratios and specific solute ... |
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| Oxygen Effects on Glass Formation of Plasma Arc Sprayed Cu47Ti33Zr11Ni8Si1 Surface Coatings |
2004 |
5 pages |
| Authors:
D. J. Sordelet; M. F. Besser; AMES LAB IA
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| A series of thermal spray experiments were performed to produce Cu47Ti33Zr11Ni8Si1 coatings from gas atomized powders synthesized with oxygen contents ranging from 0.125 to 0.79 wt.%. The amount of oxygen increased with decreasing particle size, which suggests the oxide is present as a surface film. Surface coatings were deposited using plasma arc spraying (PAS) in air and in an argon environment within an environmental chamber. The amount of amorphous phase ... |
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| High Temperature Strengths and Deformation of Ceramics |
15 DEC 2003 |
12 pages |
| Authors:
Sidney Yip; MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF NUCLEAR ENGINEERING
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| This project developed a computational modeling capability to study the theoretical strengths and deformation mechanisms of structural ceramics for high temperature applications. The approach adopted was molecular dynamics simulation based on appropriate interatomic potential models. The studies focused on ZrC that has excellent high-temperature properties, and to a lesser extent on SiC and SiO2. Strain-to-failure simulations were performed to observe the details of the structural instability and subsequent microstructural evolution. ... |
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| On an Exact Mapping and a Higher Order Born Rule for Use in Analyzing Graphene Carbon Nanotubes |
DEC 2003 |
24 pages |
| Authors:
Michael J. Leamy; Peter W. Chung; Raju Namburu; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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| As part of an effort to model single-walled graphene carbon nanotubes, a transformation is first described which maps atom locations originally on a planar sheet to atom locations on a cylindrical nanotube. The mapping is parametrized by the two components describing the chiral vector, and thus is valid for generating the atomic locations of arbitrary chirality nanotubes. Attention is then turned towards quantifying the dimensions of the unit cell, again ... |
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| Direct Fabrication of Patterned Functional Ceramic Films by Soft Solution Processing without Post-Firing |
19 NOV 2003 |
9 pages |
| Authors:
Masahiro Yoshimura; Tomoaki Watanabe; Takeshi Fujiware; Ryo Teranishi; TOKYO INST OF TECH YOKOHAMA (JAPAN) CENTER FOR MATERIALS DESIGNS MATERIALS AND STRUCTURES LAB
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| We are proposing an innovative concept and technology, Soft Solution Processing (SSP) for ceramics, which aims to achieve direct fabrication of shaped, sized, located, oriented ceramic materials from solutions without firing and/or sintering. We have successfully fabricated thin and thick films of BaTiO3, SrTiO3, BaWO4, SrMoO4, LiCoO2, and LiNiO2 by SSP in aqueous solutions from room temperature to 200 deg. C. In these experiments, interfacial reactions between a solid reactant ... |
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| Development of PZT Suspensions for Ceramic Ink-Jet Printing |
19 NOV 2003 |
7 pages |
| Authors:
B. Derby; D. H. Lee; T. Wang; D. Hall; MANCHESTER UNIV (UNITED KINGDOM) MATERIALS SCIENCE CENTER
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| The direct ink-jet printing of ceramic powders requires the development of highly fluid suspensions of ceramic particles with viscosity |
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| Predicting the Effect of Defect Distributions in the Bulk and on Surfaces of Ceramic Materials |
31 OCT 2003 |
25 pages |
| Authors:
Mark R. Levy; Robin W. Grimes; IMPERIAL COLL LONDON (UNITED KINGDOM)
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| This report results from a contract tasking Imperial College, London as follows: The contractor will investigate and ultimately develop ways to select optimum compositions for materials using atomic scale computer simulation. The particular material systems to be studied are: pyrochiores and fluorites (important in fuel cell and oxygen generator applications and as thermal barrier coatings on turbine blades in jet engines), and the perovskites, important electronic ceramics that also act ... |
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| The Challenge for Materials Design. Integrating Modeling and Computation |
08 SEP 2003 |
56 pages |
| Authors:
Craig S. Hartley; AIR FORCE OFFICE OF SCIENTIFIC RESEARCHARLINGTON VA
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| Briefing charts from presentation on "The Challenge for Material Design: Integrating Modeling and Computation." |
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| High-Temperature, High-Bandwidth Fiber Optic Pressure and Temperature Sensors for Gas Turbine Applications |
08 SEP 2003 |
8 pages |
| Authors:
Robert S. Fielder; Matthew E. Palmer; LUNA INNOVATIONS INC BLACKSBURG VA
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| The accurate measurement of gas flow conditions in the compressor, combustors, and turbines of gas turbine engines is important to assess performance, predict failure, and facilitate data-driven maintenance. Surface and point measurements of pressure and temperature in the high temperature regions of the turbine help engineers optimize performance, improve fuel mixing and burning in the combustor, and redesign compressor and turbine stages based on actual measurements. There currently exists no ... |
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| Effect of Radiation on Silicon and Borosilicate Glass |
SEP 2003 |
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| Authors:
Clark L. Allred; MASSACHUSETTS INST OF TECH CAMBRIDGE
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| A study was made that is logically divided into two parts, both involving radiation damage effects. The first is a study of the effects of neutron and gamma radiation on the dimensions of two borosilicate glasses, pyrex and Hoya SD-2. These two glasses are commonly used as substrates for silicon microelectromechanical (MEMS) devices, and radiation-induced compaction in a substrate can have deleterious effects on device performance. Results are presented for ... |
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| Concurrent Research on High Gravity (g) Combustion and Enabling Materials |
SEP 2003 |
6 pages |
| Authors:
Joseph Zelina; R. J. Kerans; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH TURBINE ENGINE DIV
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| A gas turbine engine has been proposed that uses a near constant temperature (NCT) cycle and Inter-Turbine Burner (ITB) to provide large amounts of power extraction from the low-pressure turbine. This level of energy is achieved with a modest temperature rise across the ITB. The additional energy can be used to power a large fan for an ultra-high bypass ratio transport aircraft, or to drive an alternator for large amounts ... |
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| A Characterization System for Ceramic Powders |
31 AUG 2003 |
8 pages |
| Authors:
I-Wei Chen; PENNSYLVANIA UNIV PHILADELPHIA DEPT OFMATERIALS SCIENCE AND ENGINEERING
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| The grant was initiated on April 1, 2001. We have purchased a laser particle size analyzer, a powder surface area analyzer, a mercury powder pore size analyzer, and an ultracentrifuge for powder separation. These instruments have all been installed and in operation. We have proceeded with powder and green body characterization of the bulk silicon nitride and SiAlONs. This includes the study of the effect of seeding with micrometer-sized crystals ... |
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| Fundamental Studies of Novel Contact-Damage Resistant Ceramics |
25 AUG 2003 |
20 pages |
| Authors:
Nitin P. Fadture; Subra Suresh; CONNECTICUT UNIV STORRS DEPT OF METALLURGY
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| The concept of elastic-modulus-graded ceramics for improved resistance to quasi-static contact damage (Hertzian-indentation), sliding- contact damage, and wear was investigated. In these graded materials, the in- plane elastic modulus (E) is low at the contact surface and high in the interior (substrate) with a continuous, or step-wise continuous, E-gradation in-between. Processing strategies for fabricating such E-graded ceramic composites in the A12O3(-)glass, the Si3N4(-)glass, and the Si3N4(-)SiC systems are described. The ... |
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| The Mechanisms of Creep Resistance of Advanced Ceramic Eutectics: Experiments and Modeling |
15 AUG 2003 |
46 pages |
| Authors:
Ali S. Argon; MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF MECHANICAL ENGINEERING
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| The creep resistance of the directionally solidified ceramic eutectics of alumina/cubic- zirconia was studied experimentally in the 1200-1520 degrees C, and 100-275 Mpa stress range, with associated TEM and SEM microscopy, as a generic example of ceramic eutectics. Additional (computer simulations were done both at the atomic level and by FEM methods to study: a) the core structure of pyramidal edge dislocations in alumina-that can only climb but not glide; ... |
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| Acquisition of a Nanoindenter for Research on Small-Scale Materials and Structures |
AUG 2003 |
6 pages |
| Authors:
Frank W. Zok; D. R. Clarke; N. C. MacDonald; Kimberly L. Turner; CALIFORNIA UNIV SANTA BARBARA DEPT OF MECHANICAL AND ENVIRONMENTAL ENGINEERING
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| The first project is "Matrix Enabled Damage Tolerance in Oxide Continuous Fiber Reinforced Ceramic Composites", PIs: Frank Zok, Carlos Levi and Robert McMeeking, funded by AFOSR. Here, the nanoindenter is being used for measuring the mechanical properties of fiber-matrix interfaces, through the so- called "fiber push-in" test. In essence, the test involves pushing an individual fiber past the surrounding matrix while simultaneously measuring the sliding displacement at the fiber/matrix interface. ... |
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| X-ray Diffractometer for Texture and Residual Stress Studies of Advanced Materials |
01 JUL 2003 |
7 pages |
| Authors:
Elizabeth C. Dickey; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF MATERIALS SCIENCE AND ENGINEERING
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| Through AFOSR DURIP grant # F49620-00-1-0245, a four circle goniometer x-ray diffractometer outfitted with a high temperature stage was purchased from Philips Analytical. The instrumentation facilitates residual stress measurements in highly textured materials up to 900 deg C. The instrument has significantly enhanced the AFOSR funded research efforts of the Pl on directionally solidified ceramic eutectics. Initial studies have measured the residual stresses in highly textured AlO3-ZrO2(Y2O3) eutectics as a ... |
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| Blast-Resistant Window Concepts |
JUL 2003 |
11 pages |
| Authors:
William S. Strickland; Mark Anderson; Dov Dover; AIR FORCE RESEARCH LAB TYNDALL AFB FL
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| Terrorist bombs threaten American civilians and military personnel both at home and abroad. Analysis of data from previous terror attacks indicates the largest number of injuries result from projected glass shards from shattered windows and facades. Three key issues have led to increased interest in new window materials as well as changes in building design codes: (1) actual terror attacks, (2) the threat of future terror attacks, and (3) monetary ... |
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| Measurement of Stress in Ceramic Laminates With Micro-Raman |
30 JUN 2003 |
8 pages |
| Authors:
Nina Orlovskaya; DREXEL UNIV PHILADELPHIA PA DEPT OF MATERIALS ENGINEERING
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| Residual stresses in laminate ceramic composites were measured by micro-Raman spectroscopy. The research proceeded from laminate samples preparation, which included the mixture of powders in certain proportions, grinding them up to submicron dispersity, rolling of the tapes, placing the tapes in a certain order, and hot pressing. Several different ceramic laminates, such as Ti3SiC2-ZrO2, B4C-SiC, and Si3N4-TiN, were used for the determination of residual stresses by micro-Raman. The AlMgB-TiB2 superhard ... |
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| Investigation of Operation and Characteristics of Small SPT With Discharge Chamber Walls Made of Different Ceramics |
25 JUN 2003 |
12 pages |
| Authors:
Vladimir Kim; Vyacheslav Kozlov; Alexander Skrylnikov; Alexander Veselovzorov; John M. Fife; AIR FORCE RESEARCH LAB EDWARDS AFB CA SPACE AND MISSILE PROPULSION DIV
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| This study characterizes the SPT-25 model with discharge chamber walls made of different materials, including the Russian BN-SiO2-type (BGP) ceramics and the AIN-BN-type and BN-type ceramics produced in France and in the United States, respectively. The first ceramic is used in modern SPT-70 and SPT- 100 flight designs and the others are prospective materials for SPT discharge chamber manufacturing. These materials have good thermal resistance and, according to published data, ... |
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| Chemical Precursor Routes to Ceramic Nanocylinders |
24 JUN 2003 |
6 pages |
| Authors:
Larry G. Sneddon; PENNSYLVANIA UNIV PHILADELPHIA DEPT OFCHEMISTRY
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| The objective this AFOSR sponsored project was to design and synthesize new processable chemical precursors to nonoxide ceramics that allow the formation of the ceramics in nano-structured forms. These studies demonstrated that the use of a suitably designed molecular or polymeric single- source precursor in conjunction with porous alumina nano-templating methods can be used for the systematic generation of aligned, monodispersed ensembles of boron carbide, boron nitride and silicon carbide ... |
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| Controlled Crystallization of Amorphous Oxide Fibers |
20 JUN 2003 |
35 pages |
| Authors:
Waltraud M. Kriven; ILLINOIS UNIV AT URBANA DEPT OF MATERIALS SCIENCE AND ENGINEERING
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| The goal of this work is to produce creep resistant reinforcement fibers to improve the toughness and reliability of oxide ceramic composites, which are able to withstand operating temperatures of 1600 deg. C in air. We have studied crystallization mechanisms of quenched mullite (3Al2O3 (dot) 2SiO2) and YAG (Y3Al5O12), from solid amorphous or polycrystalline spheres and determined the parameters of kinetics and thermodynamics. This has enabled us to put together ... |
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| Anomalous Defect Diffusion Near the Glass Transition |
18 JUN 2003 |
18 pages |
| Authors:
J. T. Bendler; J. J. Fontanella; M. F. Shiesinger; NAVAL ACADEMY ANNAPOLIS MD DEPT OF PHYSICS
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| Anomalous diffusion is employed to model defect motion in materials near their glass transition temperature. Even though the motion of a single defect possesses no characteristic time scale the overall effect of a concentration of defects is to produce a stretched exponential relaxation in the glass. This function has a well-defined time scale that depends on the concentration of mobile defects. In our model, the time scale diverges as the ... |
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| Physical Basis of Fragility |
18 JUN 2003 |
17 pages |
| Authors:
J. T. Bendler; J. J. Fontanella; M. F. Shlesinger; NAVAL ACADEMY ANNAPOLIS MD DEPT OF PHYSICS
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| Fragility of glass-forming liquids in the supercooled region is considered in the context of a defect diffusion theory. It is shown that a necessary condition that a liquid be 'fragile' is that there is an attractive interaction between mobile defects i.e. that the defects cluster with falling temperature. The relationship between the model parameters and a widely used fragility index is described. Each of the model parameters provides a contribution ... |
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Ceramics, Refractories and Glass
