| Improvement of Thermoelectric-Properties for Mg-Based Quaternary Compounds With Doping via Bulk Mechanical Alloying |
05 Feb 2010 |
21 pages |
| Authors:
Tatsuhiko Aizawa; SHIBAURA INST OF TECHNOLOGY (JAPAN)
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 | In the magnesium base TE material design, the solid solution formation is favored for reduction of thermal conductivity by lattice scattering effect. Since magnesium and silicon have low relative density, Mg2Si-base TE compounds are expected to improve the specific figure-of-merit. In this project, new material processing route is proposed and developed to make material search for ternary or quartic TE compounds and to make mass-production of Mg2Si-base TE materials. Effect ... |
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| Performance of Steel Stud Walls Subjected to Blast Loads |
01 Feb 2010 |
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| Authors:
Bryan Bewick; John Hoemann; Eric Williamson; TEXAS UNIV AT AUSTIN
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 | Past research has demonstrated that steel stud walls can perform well when subjected to large blast events. The construction methods needed to achieve good performance that take advantage of the inherent ductility offered by steel, however, have been costly and have often required the use of specialized connection details that allow a stud to reach its full flexural and/or tensile capacities prior to connection failure. The goal of the current ... |
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| Nano Shape Memory Alloy Composite Development and Applications |
27 Jan 2010 |
6 pages |
| Authors:
Hiroyuki Kato; HOKKAIDO UNIV SAPPORO (JAPAN)
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| The subject of this study is to process nano metallic fibers by physical method; the fibers will be prepared by ion-sputtering of target material on porous alumina membrane. As compared to conventional chemical method, e.g. the reductive method of nickel nano powders, the physical method has advantages such that the diameter of metallic fibers is controllable by changing the size of holes of the template, and it can be applied ... |
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| Modeling Explosive Cladding of Metallic Liners to Gun Tubes |
Jan 2010 |
13 pages |
| Authors:
Ernest L Baker; Jack Pincay; ARMY ARMAMENT RESEARCH DEVELOPMENT AND ENGINEERING CENTER PICATINNY ARSENAL NJ ENERGETICS WARHEADS AND MANUFACTURING TECHNOLOGY DIRECTORATE
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| A computational investigation of explosive cladding of refractory metal based materials was conducted in support of the Full Combat Systems Durable Gun Barrels Manufacturing Technology Objective (MTO) and Chromium Elimination Strategic Environmental Research and Development programs. The objective of the effort was to develop and demonstrate physics based modeling for explosive barrel cladding process design and optimization. The effort was focused on cladding modeling development, cladding process design, and optimization. ... |
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| Syntheses, Characterizations, and Applications of Molecular Metal Wires and Functional Nanomaterials |
22 Dec 2009 |
15 pages |
| Authors:
Shie-Ming Peng; Chun-hsien Chen; NATIONAL TAIWAN UNIV TAIPEI
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| This report is on research into novel extended metal atom chains and their properties, such as crystallographic, structural, magnetic, electrochemical, and electric conductive properties. |
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| Investigation of Shock Wave Attenuation in Porous Materials |
Dec 2009 |
106 pages |
| Authors:
Boey C Wai; CENTER FOR EDGE POWER MONTEREY CA
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| This thesis investigates the use of porous materials in a multi-layered armor concept. The prototype layered structure consists of an initial high-strength material to slow down the projectile and cause significant plastic deformation, followed by an orthotropic wave-spreading layer to spread shock waves laterally away from the axis of penetration and subsequently attenuate the shock waves by using a porous material to convert kinetic energy into internal energy. Based on ... |
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| Cost Increases Related to the Producer Price Index for Titanium Mill Shapes on DOD Multiyear Contracts |
29 Oct 2009 |
41 pages |
| Authors:
INSPECTOR GENERAL DEPT OF DEFENSE ARLINGTON VA
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| DOD is subject to the volatility in the titanium market when pricing titanium materials in its contracts for DOD aerospace programs because DOD does not have a strategic purchasing program for titanium. Long-term contracts with U.S. titanium producers could substantially mitigate the effect of unexpected price increases due to the market volatility of titanium pricing. Long-term contracts could also be beneficial to the U.S. titanium producers because the agreements provide ... |
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| Mechanistic Investigations of Branched Macromolecules and Metal Nanocomposites for Nonlinear Optical Applications |
26-Sep-2009 |
29 pages |
| Authors:
Goodson; Theodore III; MICHIGAN UNIV ANN ARBOR
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| Support from the Army Research Office (ARO) has provided the opportunity for studies encompassing a combined effort consisting of different experimental and synthetic methods to produce novel nonlinear optical (NLO) materials with enhanced properties. This included the development of new synthetic branched organic macromolecules with different central core groups such as benzene, nitrogen, phosphorous, carbon as well as adamantine. These investigations gave the opportunity to probe the importance of the ... |
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| Analysis of Silicon Nitride (Si3N4) for Use in a Small Recuperated Turboshaft Engine |
21-Sep-2009 |
8 pages |
| Authors:
Richard L Jr; Stark; Michael J Vick; NAVAL RESEARCH LAB WASHINGTON DC OFF-BOARD COUNTERMEASURES BRANCH
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| This analysis was performed to determine whether silicon nitride (Si3N4) could be used as a material for fabrication of the Small Recuperated Turboshaft Heavy Fuel Engine (SMART-HFE). Oxidation and volatilization of silicon nitride in the presence of water vapor has proven to be an issue under the conditions of turbine combustion. Through the use of previous research, the recession rates of Si3N4 were predicted for various operating conditions. The volatilization ... |
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| Investigation into Contact Resistance And Damage of Metal Contacts Used in RF-MEMS Switches |
Sep-2009 |
578 pages |
| Authors:
Kevin W Gilbert; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
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| This research examines the physical and electrical processes involved in lifecycle failure of Microelectromechanical (MEMS) Radio-Frequency (RF) cantilever beam ohmic contact switches. Failures of these switches generally occur at the contact, but complete details of performance of microcontacts are difficult to measure and have not been previously reported. This study investigated the mechanics of microcontact behavior by designing and constructing a novel experimental setup. Three representative contact materials of varying ... |
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| Effect of Temperature and Viscoelastic Creep on the Clamp-Up Load in Hybrid Composite/Metal Bolted Joints |
17-Aug-2009 |
152 pages |
| Authors:
Vincent Caccese; Senthil S Vel; Mauricio Fernandex; MAINE UNIV AT ORONO DEPT OF MECHANICAL ENGINEERING
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| Hybrid composite to metal bolted joints are the focus of much research due the inherent advantages that they present. In particular, they are very attractive to designers and engineers alike due to their simplicity and ease of disassembly. However, hybrid connections are particularly susceptible to metal fatigue, stress relaxation primarily due to viscoelastic creep of the composite, thermal effects due to coefficient of thermal expansion mismatch, galvanic corrosion between the ... |
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| Analysis and Testing of a Tapered End Connection for Laser Welded Steel Sandwich Panels |
15-Aug-2009 |
181 pages |
| Authors:
Vincent Caccese; Serdar Yourimaz; Lawrence Thompson; Senthil S Vei; MAINE UNIV ORONO OFFICE OF RESEARCH AND SPONSORED PROGRAMS
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| 14. ABSTRACT This report summarize the analysis and cyclic testing of a laser welded steel sandwich panel end connection. Also included are monotonic tests of stake welded lap shear coupons with welds oriented both longitudinally and transverse. Steel sandwich panels offer substantial resistance to static and dynamic loads due to their high stiffness and substantial energy absorbing capacity. Panels of this kind are interest of potential use in ships and ... |
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| Aluminum Alloy 7068 Mechanical Characterization |
Aug-2009 |
18 pages |
| Authors:
Michael Minnicino; David Gray; Paul Moy; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
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| A relatively new alloy of aluminum is being marketed as ordnance aluminum by its developer, Kasier Aluminum (Foothill Ranch, CA), owing its history to the development of ordnance applications. The aluminum alloy designation, 7068, is the strongest aluminum commercially produced. This alloy is aluminum zinc, with an advertised minimum yield strength of 99 ksi. This report characterizes extruded 7068 aluminum in terms of its elastic properties and mechanical strength, in ... |
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| Mass Spectrometric Analysis of the Electrospray Plume from an Externally Wetted Tungsten Ribbon Emitter |
Aug-2009 |
11 pages |
| Authors:
Yu-Hui Chiu; Brian W Ticknor; Shawn W Miller; AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE VEHICLES DIRECTORATE
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| Angle-resolved mass spectrometry in conjunction with retarding potential energy analysis provides information on the mechanisms of ion field evaporation and spatial distributions of the emitted ions and droplets, the latter being of particular importance in the emitter array configuration. In the present study, we conduct mass spectrometric, retarding potential, and angular distribution measurements for ions. The angle resolved measurements indicate that the spray comprises a mixture of droplets and ions. ... |
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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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| Defects Associated with Solidification of Melt-Processed Superalloys for the Aerospace Industry |
Jun-2009 |
12 pages |
| Authors:
J E Spowart; M D Asta; S H Davis; D N Seidman; P W Voorhees; T M Pollock; C F Woodward; NORTHWESTERN UNIV EVANSTON IL DEPT OF MATERIALS SCIENCE AND ENGINEERING
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| Our Materials Engineering for Affordable New Systems (MEANS) program was centered on developing an integrated computational framework for predicting the conditions under which turbine blades can be produced that are free of deleterious solidification defects. We studied the solidification process over length scales from subnanometer to millimeter and produced a theory for defect formation. Close interaction with industry was necessary to ensure the resulting computational model will be in a ... |
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| Atomic Layer Deposition Enabled Interconnect Technology for Vertical Nanowire Arrays |
Jun 2009 |
26 pages |
| Authors:
Jen-Hau Cheng; Dragos Seghete; Myongjai Lee; John B Schlager; Kris A Bertness; Norman A Sanford; Ronggui Yang; Steven M George; Y C Lee; COLORADO UNIV AT BOULDER DEPT OF MECHANICAL ENGINEERING
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| We have demonstrated an atomic layer deposition (ALD) enabled interconnect technology for vertical, c-axis oriented gallium nitride (GaN) nanowire (NW, 5-10 um in length, 80-200 nm in diameter) arrays encapsulated by Benzocyclobutene (BCB). The nano-scaled ALD multilayer is essential to provide conformal co-axial dielectric (ALDalumina)/ conductor (ALD-tungsten) coverage and precise thickness control for nanowire metallization. Furthermore, we have successfully developed a fabrication process to locally remove and connect tungsten (W) ... |
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| Initial Evaluation of Advanced Powder Metallurgy Magnesium Alloys for Armor Development |
May-2009 |
46 pages |
| Authors:
Tyrone Jones; Katsuyoshi Kondoh; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
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| The U.S. Army Research Laboratory (ARL) is interested in assessing the performance of different magnesium alloys. ARL and the Joining and Welding Research Institute (JWRI) conducted an effort to develop and evaluate advanced powder metallurgy magnesium alloys AZ31B and AMX602 (Mg-6Al-0.5Mn-2Ca/mass%) sheets. JWRI performed the mechanical and metallurgical analysis, while ARL performed the ballistic analysis. The thin-gauge magnesium alloy sheets were ballistically evaluated against the 0.22-cal. fragment-simulating projectile. The magnesium ... |
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| Frequency Domain Fluorimetry Using a Mercury Vapor Lamp |
07 Apr 2009 |
13 pages |
| Authors:
Matthew J Bohn; Michael A Lundin; Michael A Marciniak; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT/DEPT OF ENGINEERING PHYSICS
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| Frequency Domain (FD) fluorimetry, capitalizes on the frequency response function of a fluorophore and offers independence from light scatter and excitation/emission intensity variations in order to extract the sample's fluorescent lifetime. Mercury vapor lamps, a common source of industrial facility lighting, emit radiation that overlaps the UV/blue absorption spectrum of many fluorophores and may be used as an efficient and portable excitation source. The AC power modulation of mercury vapor ... |
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| A Combined Experimental and Computational Study to Examine Lateral Constraint Effects on Single-Slip Oriented Microcompression Experiments (Preprint) |
Apr-2009 |
18 pages |
| Authors:
H L Fraser; M D Uchic; D M Dimiduk; P A Shade; R Wheeler; Y S Choi; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
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| A custom in-situ SEM mechanical testing system has been used to study the compressive deformation behavior of single-slip oriented Rene N5 microcrystals. Two different compression platens were used to explore the effect of lateral stiffness on the resultant mechanical response, which approximated either a full-frictional or zero-friction case. The change in the lateral constraint of the test system had a demonstrable effect on many aspects or attributes of plastic flow: ... |
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| Novel MEMS Apparatus for In Situ Thermo-Mechanical Tensile Testing of Materials at the Micro- and Nano-Scale (Preprint) |
Apr-2009 |
6 pages |
| Authors:
M D Uchic; J Han; T Saif; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
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| We present, for the first time, a MEMS-based test methodology that potentially enables elevated-temperature mechanical tensile testing of nano- and micro-scale samples within a SEM or TEM (T 500 degrees C). Importantly, the test methodology allows for the samples to be fabricated separately from the MEMS-apparatus, a significant advancement from other test devices developed by some of the present authors. Therefore the test methodology should be applicable to the study ... |
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| A Model of Discontinuous Dynamic Recrystallization and its Application for Nickel Alloys |
Apr-2009 |
8 pages |
| Authors:
S L Semiatin; Gilles Damamme; David Piot; Frank Montheillet; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
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| A simple mesoscale model was developed for discontinuous dynamic recrystallization. The material is described on a grain scale as a set of (variable) spherical grains. Each grain is characterized by two internal variables: its diameter and dislocation density (assumed homogeneous within the grain). Each grain is then considered in turn as an inclusion, embedded in a homogeneous equivalent matrix, the properties of which are obtained by averaging over all the ... |
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| Anaerobic Biostimulation for the In Situ Precipitation and Long-Term Sequestration of Metal Sulfides |
Apr 2009 |
176 pages |
| Authors:
Mary DeFlaun; Jacquelyn Lanzon; Michael Lodato; Stephanie Henry; Tullis E Onstott; Eric Chan; Bamiedele Otemuyiwa; GEOSYNTEC CONSULTANTS TAMPA FL
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| The precipitation of dissolved metals in groundwater under anaerobic conditions has been the subject of numerous studies, but there has been very limited research on the mineralogy and the stability of these precipitates under variable geochemical conditions. Examining the mineralogy and establishing the rate of dissolution of precipitates under aerobic conditions is the subject of this SERDP supported research. A field research site was established at Site No. ST-65, a ... |
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| Environmental Effects on Fatigue Crack Growth in High Performance Aluminum Alloys |
13-Mar-2009 |
6 pages |
| Authors:
J J Williams; N Chawla; ARIZONA STATE UNIV TEMPE
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| Aluminum alloys are used in a variety of structural applications, such as aircraft wings, fuselage, etc. In addition to cyclic mechanical loads, these alloys are often subjected to aggressive corrosive environments, e.g., salt water and moisture. Thus, a comprehensive understanding of the combined effects of cyclic mechanical loading and environmental effects is necessary. |
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| Fatigue Variability of a Single Crystal Superalloy at Elevated Temperature (Preprint) |
Mar-2009 |
18 pages |
| Authors:
Reji John; JOHN PORTER; Ryan Morrissey; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
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| In order to develop more accurate life prediction tools, an improved understanding of the variability within the fatigue behavior of a material is required. Recent work has shown multiple failure mechanisms that drive the variability in fatigue life of polycrystalline titanium and nickel materials. In addition, the bimodal behavior in the fatigue response is not readily apparent when only a very small number of specimens are tested at each loading ... |
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| Laboratory Instrumentation Design Research for Scalable Next Generation Epitaxy: Non-Equilibrium Wide Application Epitaxial Patterning by Intelligent Control (NEW-EPIC). Volume 1. 3D Composition/Doping Control via Micromiror Patterned Deep UV Photodesorpt |
19-Feb-2009 |
30 pages |
| Authors:
W A Doolittle; A B Frazier; S D Burnham; David Pritchett; Daniel Billingsley; Walter Henderson; Thomas Myers; Annabell Selloni; ASL ENVIRONMENTAL SCIENCES NORTH SAANICH (BRITISH COLUMBIA)
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| A novel UV-assisted MOMBE system has been developed enabling intense UV irradiation of films during growth. High quality, heavily (unintentionally) carbon-doped GaN is successfully grown by NH3-based MOMBE and for the first time InGaN, AlGaN, and magnesium-doped GaN are demonstrated by NH3-based MOMBE. Intense UV irradiation of films during NH3-based MOMBE significantly enhances photo-desorption of species during the growth process, subsequently affecting the resultant InGaN alloy composition, carbon dopant concentration, ... |
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| Deposition of Amorphous Aluminum Alloys as a Replacement for Aluminum Cladding |
05-Feb-2009 |
22 pages |
| Authors:
Shmuel Eidelman; Ben Gauthier; Igor Vidensky; Nicole Tailleart; John Scully; ENIGMATICS INC COLLEGE PARK MD
|
| PRESENTATION OUTLINE: Background * Aging aircraft challenge * Multifunctional Coatings for AA-2024 * Desirable coating Attributes. * Project Overview * Alloy Development * Pulsed Thermal Spray * Nanostructured Al-Co-Ce * Cyclic Polarization * Sacrificial Anode/Inhibitor Release * ASTM B117 Salt Fog * Repairing Damage Samples * Summary * Future Work. |
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| AC-Induced Bias Potential Effect on Corrosion of Steels |
05-Feb-2009 |
38 pages |
| Authors:
J E Jackson; A N Lasseigne; D L Olson; B Mishra; GENERATION 2 MATERIALS TECHNOLOGY LLC FIRESTONE CO
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| Overview of briefing charts: Background, Literature review, Magnetocorrosion JIP, Proposed AC Corrosion Models, AC Simulated Corrosion testing, Stainless steel pipe and coating, Cathodic protection, Experimental setup, Preliminary test arrangement, Current test arrangement, Experimental analysis techniques, Assessment of models and Proposed Research. |
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| Magnesium Technology and Manufacturing for Ultra Lightweight Armored Ground Vehicles |
Feb-2009 |
14 pages |
| Authors:
Kyu Cho; Paul Moy; Tomoko Sano; Kevin Doherty; Chian Yen; George Gazonas; Jonathan Montgomery; Bruce Davis; Rick DeLorme; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| The current paper summarizes magnesium alloy metallurgy and wrought manufacturing with an initial emphasis on the Elektron WE43 alloy system for lightweight armored ground vehicle applications. Engineering design factors are reviewed and initial mechanical property data are presented along with ballistic results and findings from blast simulations. Finally the future role of magnesium alloys in ultra light metallic armor is discussed in terms of material development and application. |
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| Microstructural and Mechanical Behavior Characterization of Ultrasonically Consolidated Titanium-Aluminum Laminates |
Feb-2009 |
12 pages |
| Authors:
DATTATRAYA DANDEKAR; Tomoko Sano; James Catalano; Daniel Casem; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
|
| Multilayered hybrid metal laminates have been studied for structural applications due to their potential for higher strength, toughness, and stiffness. The goal of this study was to modify the microstructure and mechanical properties of commercial purity titanium (CP-Ti) and 1100 aluminum (Al) laminates for potential applications in mine blast mitigation. Alternating layers of 50 micron thick CP-Ti and Al layers were ultrasonically consolidated. To provide high hardness and stiffness, the ... |
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| Corrosion Protection of Aluminum Alloys by Vanadate Pigments in Epoxy Primers |
Feb-2009 |
19 pages |
| Authors:
M Iannuzzi; K Evans; J E Ramos-Nervi; CORROSION AND MATERIALS TECHNOLOGY LAB DUBLIN OH
|
| ONGOING WORK (1) Artificial scratch cell: The artificial scratch cell setup is being used to further evaluate whether meta-vanadates released from the coating could protect bare Al surfaces. (2) Coating degradation: A detailed EIS analysis on coatings with and without intentional defects is also being conducted. Results thus far have shown lower break point frequencies and larger Z(10mHz) values when vanadates were added to the primer in line with the ... |
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| Thin Foil Test System Development (Preprint) |
Feb 2009 |
16 pages |
| Authors:
Ryan J Morrissey; Garth Wilks; Michael Uchic; Reji John; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
|
| The need to accurately determine the mechanical properties of thin foil materials has grown in recent years as the emphasis on hypersonic vehicles and access to space has also increased. In order to meet this need, two separate test systems have been developed in-house as part of a comprehensive program to advance state-of-the-art testing capabilities for thin foils. The first test system, developed using a conventional MTS hydraulic load frame ... |
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| Development of a Multi-Scale Methodology for Prediction of the Microscopic Anisotropic Stress-Strain Response of Textured Metals under Dynamic Loading |
21-Jan-2009 |
69 pages |
| Authors:
Oana Cazacu; FLORIDA UNIV SHALIMAR DEPT OF MECHANICAL AND AEROSPACE ENGINEERING
|
| This report documents a comprehensive experimental and theoretical investigation of the deformation behavior of high-purity, polycrystalline alpha-titanium. A series of monotonic uniaxial compression and tension tests were carried out at room temperature under quasi-static conditions to quantify the plastic anisotropy and the tension-compression asymmetry of this material. The evolution of microstructure and texture during deformation was studied using optical image microscopy (OIM) and neutron-diffraction techniques to elucidate the role of ... |
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| Liquid Metal Anode for JP-8 Fuel Cell |
15-Jan-2009 |
63 pages |
| Authors:
Thomas Tao; Ralph White; Stephen Klotz; CELLTECH POWER LLC WESTBOROUGH MA
|
| Report developed under STTR contract W911NF-08-C-0075 for topic A08-T007. JP-8 is a high-energy density liquid fuel available to the soldier, but its electrochemical oxidation in a fuel cell is problematic. The purpose of this effort is to advance the development of a liquid metal based fuel cell operating directly on JP-8 for application in a field portable battery charger. During Phase 1 an evaluation was performed of a range of ... |
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| Titanium: Industrial Base, Price Trends, and Technology Initiatives |
Jan-2009 |
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| Authors:
Obaid Younossi; Thomas Lang; Somi Seong; Benjamin W Goldsmith; Michael Neumann; RAND CORP SANTA MONICA CA
|
| Titanium accounts for a significant portion of the structural weight of many aircraft. Its high strength-to-weight ratio, high strength at high temperatures, corrosion resistance, and thermal stability make it ideal for airframe structures. However, in recent years a combination of multiple factors has caused a major spike in titanium prices that is expected to significantly influence the acquisition costs of future aircraft. This monograph examines the titanium industrial base, titanium ... |
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| Compositional Variations Between Different Generations of Gamma Precipitates Forming During Continuous Cooling of a Commercial Nickel-Base Superalloy |
Jan 2009 |
11 pages |
| Authors:
J Y Hwang; S Nag; A R Singh; R Srinivasan; J Tiley; G B Viswanathan; H L Fraser; R Banerjee; NORTH TEXAS STATE UNIV DENTON
|
| The compositional and microstructural evolution of different generations of precipitates of the ordered gamma' phase during the continuous cooling, followed by isothermal aging, of a commercial nickel-base superalloy. Rene 88DT, has been characterized by three dimensional atom probe (3DAP) tomography coupled with energy-filtered transmission electron microscopy (EFTEM) studies. After solutionizing in the single gamma-phase field, during continuous cooling at a relatively slow rate (24 deg C/Min), the first generation primary ... |
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| Evaluation of a Simple Proof Test of Planar Ferrite Cores |
20-Dec-2008 |
14 pages |
| Authors:
de la; Aldrich Cruz; David Witkin; AEROSPACE CORP EL SEGUNDO CA
|
| Ferrites are soft magnetic materials that have a wide range of uses in microwave circuits. Many otherwise flight-qualified parts may have a variety of defects arising from fabrication and handling. A finite-element analysis (FEA) was performed to design a simple proof test for a particular planar ferrite core geometry. A 3-point bend test and three different geometries of 4-point bend tests were modeled to determine the distribution of tensile stress ... |
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| Comparison of the Noise Penalty of a Raman Amplifier Versus an Erbium-doped Fiber Amplifier for Long-haul Analog Fiber-optic Links |
17-Dec-2008 |
17 pages |
| Authors:
Preetpaul S Devgan; John F Diehl; Vincent J Urick; Keith J Williams; NAVAL RESEARCH LAB WASHINGTON DC
|
| A Raman amplifier is compared to an erbium-doped fiber amplifier for a 14 km analog fiber-optic link requiring the amplifier pump at the end of the link. The noise penalty for each amplifier at a given photocurrent is measured and compared. An analytical expression comparing the analog metrics as a function of noise penalty and photocurrent for different amplifiers is derived and used. The Raman amplifier has a lower noise ... |
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| History and Performance of FEI Space-Class Oscillators |
01-Dec-2008 |
23 pages |
| Authors:
M Bloch; O Mancini; T McClelland; FREQUENCY ELECTRONICS INC MITCHEL FIELD NY
|
| An indispensable component of any space vehicle is the onboard master oscillator. The proper operation of the entire payload is dependent on the performance of the master oscillator or the onboard clock. Frequency Electronics, Inc. (FEI) has been a key supplier of high reliability oscillators for space applications since 1963, and in this paper we will present a short history of oscillators for space applications that include quartz-based oscillators, rubidium ... |
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| Development of a Ballistic Specification for Magnesium Alloy AZ31B |
Dec-2008 |
52 pages |
| Authors:
Tyrone L Jones; Richard D DeLorme; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
|
| The U.S. Army Research Laboratory (ARL) and Magnesium Elektron North America (MENA) have conducted a joint effort to develop and evaluate rolled plate in commercially available magnesium alloy-temper AZ31B-H24. MENA produced the rolled product and conducted the mechanical analysis, while ARL performed the ballistic analysis. The magnesium alloy plates were parametrically compared with the minimum performance requirements of aluminum alloy 5083-H131 temper rolled plate using various armor-piercing and fragment-simulating projectiles ... |
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| Mobility, Geochemistry, and Speciation of Tungsten |
Dec-2008 |
8 pages |
| Authors:
A J Bednar; W T Jones; R E Boyd; R A Kirgan; M A Chappell; J L Clausen; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS ENVIRONMENTAL LAB
|
| Tungsten metal is used in many industrial, military, and consumer applications, and interest in its biogeochemistry is increasing partially due to its potential mobility and biological effects. Recent studies have investigated the geochemistry of tungsten from the laboratory to field scale, to determine its mobility and toxicity. Tungsten exists in most environmental matrices as the soluble and mobile tungstate anion, although polymerization to form poly- and heteropoly- tungstates has been ... |
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| Advancements in Steel for Weight Reduction of P900 Armor Plate |
Dec-2008 |
8 pages |
| Authors:
R A Howell; J S Van Montgomery; D C Aken; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD SURVIVABILITY MATERIALS BRANCH
|
| Ballistic tests were conducted on a high manganese and high aluminum austenitic steel that is age hardenable. These lightweight steels (12 to 18% lower in density) were investigated as alternatives to MIL-PRF- 32269 steel alloys for application in P900 perforated armor currently used for Army ground combat systems. Two steel plates with nominal composition in weight percent of Fe-30Mn-9Al-1Si-0.9C-0.5Mo were evaluated for V50 against 0.30 caliber armor piercing and 0.50 ... |
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| Blast and Fragment Protective Sandwich Panel Concepts for Stainless Steel Monohull Designs |
21-Oct-2008 |
258 pages |
| Authors:
H G Wadley; VIRGINIA UNIV CHARLOTTESVILLE OFFICE OF SPONSORED PROGRAMS
|
| The prevention or mitigation of ship hull damage from underwater explosions (UNDEX) is of vital need for surface combatant Naval ships. This research program sought to devise blast and ballistic protection concepts applicable to the design and fabrication of ship hull structures using AL6XN stainless steel sandwich panel constructions, which met threat and protection levels defined by the Navy. Efforts were undertaken in two phases to design, fabricate, experimentally investigate ... |
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| Minerals Price Increases and Volatility: Causes and Consequences |
03-Oct-2008 |
|
| Authors:
Stephen Cooney; Dick K Nanto; LIBRARY OF CONGRESS WASHINGTON DC CONGRESSIONAL RESEARCH SERVICE
|
| A rise in the prices of minerals has had a major impact on U.S. manufacturers and consumers. Mineral prices have risen while the economy as a whole has entered a period of slowing growth. This has created serious difficulties for consuming industries and concern in Congress. This report reviews the increases in price across a wide range of metals commodities. Prices have at least nearly doubled between 2001 and 2008. ... |
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| Investigation into the Effect of Reagent Choice on the Dielectric Properties of the Ferroelectric Oxides Ba(MTa)0.05Ti0.9O3 (where M=Sc, Er, Ho or Y) |
01-Oct-2008 |
24 pages |
| Authors:
Virginia L Miller; Steven C Tidrow; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
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| This report investigates the effects of reagent choice on the physical properties of ferroelectric oxides of the composition Ba(MTa)0.05Ti0.9O3 (M=Sc, Er, Ho or V). These materials are of particular interest because they possess relatively low to medium dielectric constants and improved tunabilities. In this project, samples of Ba(MTa)0.05Ti0.9O3 (M=Sc, Er, Ho or Y) were prepared using two different synthetic methods. The first method consisted of heating a stoichiometric mixture of ... |
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| Variability in Room Temperature Fatigue Life of Alpha+Beta Processed Ti-6Al-4V (Preprint) |
Oct-2008 |
17 pages |
| Authors:
Reji John; JOHN PORTER; Patrick J Golden; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
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| In this program, smooth bar fatigue tests were conducted by several laboratories on the same lot of Ti-6Al-4V forged plate material. Multiple stress ratios and stress levels were tested to generate a fully populated stress-life curve. The tests, however, did not typically consist of many repeats. The approach of this work is to conduct a statistically significant number of repeated fatigue tests at a few loading conditions. A similar approach ... |
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| Mechanical Response of an Al-PTFE Composite to Uniaxial Compression Over a Range of Strain Rates and Temperatures |
01-Sep-2008 |
28 pages |
| Authors:
Daniel T Casem; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
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| Compressive stress-strain curves were generated for a pressed and sintered mixture of polytetrafluoroethylene and aluminum powders. Experiments were performed at strain rates ranging from 0.001 to 8000/s using a servo-hydraulic load frame and a split Hopkinson pressure bar. High-rate experiments were also performed over a temperature range of 22-78 C. The data is fit to the Johnson-Cook and Modified Johnson-Cook constitutive equations and also to a Zerilli-Armstrong equation adapted for ... |
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| Nominal Versus Local Shot-Peening Effects on Fatigue Lifetime in Ti-6Al-2Sn-4Zr-6Mo at Elevated Temperature (Preprint) |
Sep-2008 |
26 pages |
| Authors:
S K Jha; R John; J M Larsen; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
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| A study of the elevated temperature fatigue lifetime variability in the shot-peened condition of the a+b titanium alloy, -Ti-6Al-2Sn-4Zr-6Mo, is presented. It is shown that failures separate into two distributions: (1) governed by the nominal residual stress profile, promoting subsurface crack initiation and longer lifetimes, and (2) the life-limiting behavior that is controlled by localized material-shot-peening interaction. In the residual-stress-free condition, failures occurred predominantly by surface crack initiation at the ... |
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| Effect of High Temperature Exposure on the Mechanical Properties of Cold Expanded Open Holes in 7050-T7451 Aluminium Alloy |
Sep-2008 |
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| Authors:
Q Liu; P Baburamani; C Loader; DEFENCE SCIENCE AND TECHNOLOGY ORGANISATION VICTORIA (AUSTRALIA) AIR VEHICLES DIV
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| Cold expansion of fastener holes has been widely used in the manufacture, maintenance and repair of airframe components to provide beneficial compressive residual stresses around fastener holes and to extend their fatigue life. However, some components may experience exposure to high temperatures due to operational, maintenance or accidental factors. The high temperature exposure could lead to relaxation of compressive residual stresses and potentially affect the component's properties such as fatigue ... |
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| The Mean vs Life-Limiting Fatigue Response of a Ni-Base Superalloy, Part 1: Mechanisms (Preprint) |
Sep-2008 |
28 pages |
| Authors:
S K Jha; J M Larsen; M J Caton; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
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| The fatigue variability behavior of a powder metallurgy (P/M) Nickel-base superalloy, IN100, was studied from the perspective of the prediction of useful-lifetime. We found that stress level produced separate effects on the mean-fatigue behavior and the life-limiting mechanism. In the present IN100 material, this separation of responses is suggested to be related to the different levels of heterogeneity induced by the number density and the size distribution of constituent particles ... |
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Metallurgy and Metallography
