| Mathematical and Computer Analysis of the Interaction Between both Stress and Electron Waves and Elastic Stresses Due to the Rotation of Grains to Promote Fracture Resistance and Electrical Conductivity in Ceramic Materials |
05 Jan 2010 |
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| Authors:
Christine M Kennefick; LIBRARY OF CONGRESS WASHINGTON DC CONGRESSIONAL RESEARCH SERVICE
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 | The conditions on elastic displacement and stress in a material that will promote reflection and transmission of an incoming wave are calculated. It is found, for example, that to optimize reflection and transmission, scalar potentials of the displacement in the wave and in the material will be related to rotations in planes perpendicular and parallel to the direction of propagation to the wave. When a pulse is constructed and its ... |
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| 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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| Fatigue Behavior of an Advanced SiC/SiC Composite at Elevated Temperature in Air and in Steam |
Dec 2009 |
151 pages |
| Authors:
Devon T Christensen; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
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 | The fatigue behavior of an advanced Silicon Carbide/Silicon Carbide (SiC/SiC) ceramic matrix composite (CMC) was investigated at 1200 deg C in laboratory air and in steam environments. The composite consisted of a SiC matrix reinforced with Boron Nitride (BN) coated Hi-Nicalon fibers woven into eight-harness-satin (8HS) weave plies. Tensile stress-strain behavior and tensile properties were also evaluated at 1200 deg C. Tension-tension fatigue tests were conducted in both laboratory air ... |
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| Investigation of Advanced Personnel Armor Using Layered Construction |
Dec 2009 |
108 pages |
| Authors:
Ong C Roy; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF PHYSICS
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| A new method of constructing personnel armor is investigated. It comprises of a very hard 1st layer to deform and fracture the projectile, an orthotropic 2nd layer to slow down the shock wave propagation in the through-thickness direction, whilst allowing rapid propagation in the transverse directions, a 3rd porous layer to absorb the shock wave energy through PV-work, and a 4th layer to provide confinement for the porous medium. Based ... |
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| Development of Ceramic Laser Element |
24 Nov 2009 |
13 pages |
| Authors:
Akio Ikesue; Yan L Aung; WORLD-LAB CO LTD NAGOYA (JAPAN)
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| Practical laser generation from polycrystalline ceramic materials has become available; furthermore, it is expected that ceramic laser technology will completely surpass the conventional glass and single crystal laser technologies in the future. In this work development of high quality ceramic laser materials was successfully done by control on macro-, micro- and nano-structural refinement. Transparency and optical homogeneity were confirmed to be high enough for the development of high power laser ... |
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| Effects of Phase Change and Oxygen Permeability in Oxide Scales on Oxidation Kinetics of ZrB2 and HfB2 (POSTPRINT) |
Nov 2009 |
11 pages |
| Authors:
Triplicane A Parthasarathy; Robert A Rapp; Mark Opeka; Ronald J Kerans; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
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| A wide range of experimental data on the oxidation of ZrB2 and HfB2 as a function of temperature (800 - 1500 degrees Celsius) is interpreted using a mechanistic model that relaxes two significant assumptions made in prior work. First, inclusion of the effect of volume change associated with monoclinic to tetragonal phase change of the MeO2 phases is found to rationalize the observations by several investigators of abrupt changes in ... |
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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
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| 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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| Nondestructive Damage Characterization of Alumina Ceramics |
Jul 2009 |
36 pages |
| Authors:
Raymond E Brennan; James M Sands; William H Green; Jian H Yu; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
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| A qualitative evaluation of surface and bulk damage and a quantitative percent damage assessment were used to compare the integrity of several nondestructive characterization techniques. X-ray digital radiography and ultrasound C-scan imaging were compared for their ability to detect damage in aluminum-backed alumina test samples. Incremental damage was produced by two different methods, including high-mass, low-velocity drop tower testing for large crack and low mass generation, and highvelocity fragment-simulating projectile ... |
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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
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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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| 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:
Steven Miller; Ernest Chin; William Green; James Campbell; Douglas M Slusark; M V Demirbas; Andrew Portune; Richard A Haber; Raymond Brennan; 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
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| 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
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| 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
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| 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
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| 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 |
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| 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
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| 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
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| 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
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| 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
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| 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
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| 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
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| 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
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| 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
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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 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
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| 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
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| 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
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| 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
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| 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
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| 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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Ceramics, Refractories and Glass
