| Development of High ZT Thermoelectric Materials with Nanostructure for Energy Applications |
03 Mar 2010 |
19 pages |
| Authors:
Maw-Kuen Wu; Yang-Yuan Chen; ACADEMIA SINICA NANKANG TAIPEI (TAIWAN) INST OF PHYSICS
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 | Three subtasks were performed in this research study and the respective findings are described here. A) Investigation of the system of surface modified nanostructured bulk: Our studies show that the CuFeSe2 thin film on Si (or SiO2) substrates exhibit large thermal power in the order of 1300 microvolt/K at approximately 300K. We conclude that the thinner films have the higher thermal conductivity. At 300K, the magnitude of thermal conductivity 8.8 ... |
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| Consideration of Wear Rates at High Velocity |
Mar 2010 |
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| Authors:
Chad S Hale; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
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 | The development of the research presented here is one in which high velocity relative sliding motion between two bodies in contact has been considered. The experimental results of a VascoMax 300 maraging steel slipper sliding on an AISI 1080 steel rail during a January 2008 sled test mission were considered for the determination of high velocity wear rates. The numerical model, based on a metallographic study of a test slipper, ... |
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| The Effective Behavior of Heterogeneous Ferromagnetic Materials |
31 Jan 2010 |
3 pages |
| Authors:
WASHINGTON UNIV SEATTLE
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| In the project, we have studied a variety of heterogeneous ferromagnetic materials, including ferromagnetic shape memory alloys, multiferroic materials, and ferromagnetic composites. The main achievements have been summarized as following: 1. A constrained theory of magnetoelastic materials has been developed to study the effective behavior of single-crystalline and polycrystalline ferromagnetic shape memory alloys (FSMA) based on nonlinear homogenization theory and variational principle. The actuation strain induced by domain switching under ... |
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| Aluminum Based Nanoeutectics: Synthesis and Microstructure |
30 Jan 2010 |
5 pages |
| Authors:
Kamanio Chattopadhyay; INDIAN INST OF SCIENCE BANGALORE (INDIA)
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| The primary aim of the project was to explore the possibility of synthesizing high strength multiphase eutectic alloys based on aluminium which also exhibits reasonable ductility. The approach used was to develop a multiscale microstructure including nanometer length scale eutectic colony using ternary alloys and evaluate their deformation behavior. We have carried out work on two alloy systems, Al-Cu-Si and Al-Fe-Ni. Both exhibit ternary eutectic reaction. The microstructures were manipulated ... |
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| Enhancement of Grain Refined Microstructure in a Nanostructured Metals via Ultrahigh Pressure Hydrostatic Consolidation Process - Construction of Master Sintering Curve (MSC) and Its Application to Densification of Al-Mg Alloy |
30 Jan 2010 |
9 pages |
| Authors:
Sangmok Lee; ASIAN OFFICE OF AEROSPACE RESEARCH AND DEVELOPMENT APO AP 96337-0007
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| Previously Al-Mg alloy was densified by hot isostatic processing and subsequently consolidated by hydrostatic extrusion. Through this process high strength and high formability nanostructured bulk Al-Mg alloy was fabricated. However, it is important to handle parametric control in powder metallurgical processing in terms of relative density, which is closely associated with its mechanical properties in acquiring a material of a desired property. At current stage processing parameter of density function ... |
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| Influence of Experimental Conditions on the Outcome of Laboratory Investigations Using Natural Coastal Seawaters |
Jan 2010 |
9 pages |
| Authors:
Jason S Lee; Richard I Ray; Brenda J Little; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS OCEANOGRAPHY DIV
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| Methods for handling and storing natural coastal seawater, particularly methods for deaeration over time, influenced the chemistry and microflora. Bubbling nitrogen into natural seawater to achieve an anaerobic condition was not conducive to the growth of sulfate-reducing bacteria (SRB). Despite a higher initial dissolved sulfate concentration and higher total organic carbon in Persian Gulf seawater, higher dissolved sulfide concentrations and SRB populations were measured in Key West, Florida, seawater under ... |
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| Nitrogen Rings and Cages Stabilized by Metallic Atoms |
18 Dec 2009 |
6 pages |
| Authors:
Gabriel Merino; Manuel Villanueva; Francisco Tenorio; Oscar Jimenez-Halla; America Bravo; Kristel Garcia; Cristina Santiago; UNIVERSIDAD DE GUANAJUATO DEPARTAMENTO DE QUIMICA
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| Over the last four years, our research has been focused on the prediction of new molecular species. The initial aim of this project was to study on paper new nitrogen compounds that were stabilized by metal centers. We did not find any new attractive nitrogen species. However, the algorithms developed during this project are universal and allow us to study other interesting chemical systems like silicon-lithium clusters. Particularly, we developed ... |
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| Dynamic Loading Characteristics in Metals and Composites |
Dec 2009 |
54 pages |
| Authors:
Kian Sing Tan; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| This study investigates the mechanical characteristics of aluminum alloy AA3003-H14 when it is subjected to dynamic axial loads at low strain rates of less than 1/s. The tensile experiments show that both the ultimate and yield stresses, as well as the absorbed strain energy, increase with strain rate. Moreover, the strains at yield, ultimate load and fracture show positive sensitivity to strain rate. On the other hand, when the material ... |
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| Prediction of Formation of Amorphous Alloys During Annealing of Ti-binary Alloys and Validation of the Same |
22 Nov 2009 |
78 pages |
| Authors:
S Ranganathan; NATIONAL METALLURGICAL LAB JAMSHEDPUR (INDIA)
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| Observation of an amorphous phase produced on annealing has excited scientists since the process can be easily controlled leading to bulk amorphous alloys that can find several technological applications. However, this phenomenon has to be explored further and understood in order to exploit it. It is important to understand the thermodynamics of this unusual phase transformation. This can lead to a better understanding of the fundamental aspects of this process. ... |
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| Templated Synthesis of Aluminum Nanoparticles - A New Route to Stable Energetic Materials |
05-Nov-2009 |
5 pages |
| Authors:
Heting Li; Mohammed J Meziani; Fushen Lu; Christopher E Bunker; Elena A Guliants; Ya-Ping Sun; CLEMSON UNIV SC
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| Nanoscale structural cavities in ionomer membrane films were used as templates for the facile synthesis of small aluminum nanoparticles via catalytic decomposition of an alane precursor. The loading of reactive aluminum in the composite film could be varied, up to more than half of the film weight. While the embedded nanoparticles were protected by the membrane structure from any significant oxidation for the composite films to exhibit surprising stability in ... |
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| Microstructural Design & Optimization of Highly Filled Epoxy Based Composites |
Nov-2009 |
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| Authors:
Bradley White; Jennifer L Jordan; D W Richards; Jonathan E Spowart; Naresh N Thadhani; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| The dynamic mechanical properties of multi-constituent particulate composites, consisting of individual Ni and Al particles dispersed in an epoxy matrix are investigated in this study. Properties of such composites depend on the mechanical and physical properties of the individual components; their loading density; the shape and size of the particles; the interfacial adhesion; residual stresses; and matrix porosity. These multi-phase particulate composites systems, particularly those with high fill densities, have ... |
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| Factors Contributing to Corrosion of Steel Pilings in Duluth-Superior Harbor |
Nov 2009 |
14 pages |
| Authors:
Richard I Ray; Jason S Lee; Brenda J Little; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS OCEANOGRAPHY DIV
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| Field observations and laboratory testing were used to conclude that aggressive localized corrosion of carbon steel pilings in Duluth-Superior Harbor, Minnesota and Wisconsin, is caused by the following sequence of biological, chemical, and physical events. Iron-oxidizing bacteria colonize the carbon steel sheet pilings and produce tubercles, which are made up of intact and/or partially degraded remains of bacterial cells mixed with amorphous hydrous ferric oxides. The reducing conditions beneath the ... |
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| Stress Field Evolution in a Ball Bearing Raceway Fatigue Spall (PREPRINT) |
Oct-2009 |
40 pages |
| Authors:
Nagaraj K Arakere; Nathan Branch; Vaughn Svendsen; Nelson H Forster; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIRECTORATE
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| The governing mechanisms of fatigue spall propagation in ball bearing inner raceways are investigated through the use of elastic-plastic finite element modeling, X-Ray Diffraction, and the visual inspection of fatigue spall cracks. The model simulates multiple ball impacts with a fatigue spall's edge in a 208 size ball bearing operating at 10,000 rpm. Ball impacts are shown to cause severe plastic deformation within the spall edge and induce tensile residual ... |
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| Microplasma Channels and Large Arrays: Applications to Photomedicine, Microlasers, and Reactors on a Chip |
Oct 2009 |
20 pages |
| Authors:
J G Eden; ILLINOIS UNIV AT URBANA DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
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| Under the support of AFOSR grant no. FA9550-07-1-0003, our laboratory at the University of Illinois has pursued the science and applications of microcavity plasmas, both as single devices and in the form of large arrays. Because of its unique properties, microplasma technology has (we believe) profound implications for photonics and electronics, with applications ranging from general lighting to biomedical diagnostics. During the past 3 years, the following milestones have been ... |
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| Multiscale Modeling of Metallic Microstructures: From Dislocations to Plasticity |
Sep 2009 |
8 pages |
| Authors:
Jeffrey M Rickman; Mikko P Haataja; David J Srolovitz; Richard A LeSar; LEHIGH UNIV BETHLEHEM PA DEPT OF MATERIALS SCIENCE AND ENGINEERING
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| The goal of this research program has been to establish a quantitative link between important strengthening mechanisms and the observed stress-strain behavior of complex, metallic aerospace materials via a modeling strategy involving mesoscale dislocation dynamics (DD) simulations and spatial homogenization. In addition, we have sought to understand better the role of cracks and grain boundaries in determining mechanical behavior, and the impact of obstacles on the formation of dislocation substructures. ... |
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| Galvanic Corrosion in Silicon Microsystems: Finite Element Simulation Tool Development |
28 Aug 2009 |
7 pages |
| Authors:
Conrad R Stoldt; COLORADO UNIV AT BOULDER OFFICE OF CONTRACTS AND GRANTS
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| Many microsystems fabrication technologies currently employ a metallic overlayer, such as gold, in electrical contact with silicon (Si) structural layers. During postprocessing in hydrofluoric acid based solutions, a galvanic cell is created between the silicon and the metallic layer. As a consequence, autonomous corrosion (etching) of the silicon layer occurs forming nanoscale porosity at the thin film surface and grain boundaries. Over the past 24 months, our ARO sponsored work ... |
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| Modeling Effects of Crystalline Microstructure, Energy Storage Mechanisms, and Residual Volume Changes on Penetration Resistance of Precipitate-Hardened Aluminum Alloys |
Aug-2009 |
14 pages |
| Authors:
John D Clayton; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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| An anisotropic nonlinear crystal mechanics model is developed for a class of ductile aluminum alloys, with the intent of relating microscopic features and properties to performance of the alloys deformed at high strain rates that may arise during impact and blast events. A direct numerical simulation of dynamic tensile deformation of an aluminum polycrystal demonstrates a tendency for shear localization to occur in regions of the microstructure where the ratio ... |
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| Multiscale Computations of Microcracking Solids |
08-Jul-2009 |
9 pages |
| Authors:
Ted Belytschko; NORTHWESTERN UNIV EVANSTON IL
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| New multiscale methods have been developed for the study of microcracking and dislocations. The multiscale method for microcracking aggregates the effect of an arbitrary number of cracks at the micro level into a single equivalent crack at the macrolevel. The methodology is based on the concept of a perforated unit cell, which excludes all subdomains of the unit cell where the material loses stability in the averaging operations. We have ... |
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| Nature of Molecular Interactions of Peptides with Gold, Palladium, and Pd-Au Bimetal Surfaces in Aqueous Solution |
24-Jun-2009 |
12 pages |
| Authors:
Ruth Pachter; Hendrik Heinz; Barry L Farmer; Ras B Pandey; Joseph N Slocik; Soumya S Patnaik; Rajesh R Naik; AKRON UNIV OH POLYMER ENGINEERING CENTER
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| We investigated molecular interactions involved in the selective binding of several short peptides derived from phage-display techniques (8-12 amino acids, excluding Cys) to surfaces of Au, Pd, and Pd-Au bimetal. Changes in chain conformation from the solution to the adsorbed state over the course of multiple nanoseconds suggest that the peptides preferably interact with vacant sites of the face-centered cubic lattice above the metal surface. Residues that contribute to binding ... |
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| Defense Management: Observations on DOD's Fiscal Year 2010 Budget Request for Corrosion Prevention and Control |
01-Jun-2009 |
22 pages |
| Authors:
GOVERNMENT ACCOUNTABILITY OFFICE WASHINGTON DC
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| This report formally transmits the attached briefing in response to section 2228(e) of title 10 of the United States Code (see enclosure I). The statute requires the Comptroller General to provide an analysis of the Department of Defense's budget submission for corrosion prevention and control, as well as an analysis of the corrosion report accompanying defense budget materials, and provide the results to the congressional defense committees within 60 days ... |
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| Defense Management: Observations on DOD's Analysis of Options for Improving Corrosion Prevention and Control through Earlier Planning in the Requirements and Acquisition Processes |
29-May-2009 |
23 pages |
| Authors:
GOVERNMENT ACCOUNTABILITY OFFICE WASHINGTON DC
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| The Department of Defense (DOD), through its costs of corrosion studies, has identified nearly $12 billion in annual corrosion costs (not including Air Force aircraft and missiles). Corrosion also affects equipment readiness and safety. For many years, DOD has recognized that earlier planning could lead to corrosion prevention and control benefits. For example, In 2003, the Under Secretary of Defense for Acquisition, Technology, and Logistics issued a policy memorandum stating ... |
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| Crystallization Augmentation of Engineering Thermoplastics through Dispersion of Silicon-Containing Nanoparticles |
26-Apr-2009 |
3 pages |
| Authors:
Joseph M Mabry; Gregory R Yandek; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
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| The mechanical properties and environmental durability of engineering thermoplastics are generally dependent on their degree of molecular ordering. Processing conditions affect observed microstructures in this class of materials and costly annealing procedures can be required to generate adequate levels of crystallinity. It is therefore beneficial to not only develop an understanding of the fundamental physics governing ordering transitions, but to be able to use such knowledge to assert control over ... |
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| Micromechanics of Damage Accumulation in Micro- and Nano-Scale Laminates for Microelectromechanical Systems |
06-Apr-2009 |
138 pages |
| Authors:
Christopher L Muhlstein; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF MATERIALS SCIENCE AND ENGINEERING
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| In this program we used a combination of microscale mechanical testing methods and nanoindentation to ascertain the deformation, fracture, and fatigue properties of the materials. A variety of materials characterization tools were then used to establish the chemistry)' and structure of the films. This study has revealed that the stability of nanograined metals, especially in the presence of cyclic loading, is poor in comparison to coarser (micron-scale) grained materials. Moreover, ... |
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| Probabilistic Sensitivity Analysis of Fretting Fatigue (Preprint) |
Apr-2009 |
14 pages |
| Authors:
Patrick J Golden; Harry R Millwater; Xiaobin Yang; TEXAS UNIV AT SAN ANTONIO DEPT OF MECHANICAL ENGINEERING AND BIOMECHANICS
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| A probabilistic analysis of the fatigue life of specimens subject to fretting fatigue was carried out. A mechanics based fretting life analysis was applied that accounted for the local stress gradient at the edge of contact. The random variables in the analysis included the initial crack size, coefficient of friction, crack growth rate law, and the contact pad profile. The variation in pad profiles was determined through statistical analysis of ... |
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| Moisture-Induced Delayed Alumina Scale Spallation on a Ni(Pt)Al Coating (Preprint) |
Apr-2009 |
32 pages |
| Authors:
James L Smialek; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH GLENN RESEARCH CENTER
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| Delayed scale failure was examined for samples of a Ni(Pt)Al-coated CMSX4 single crystal superalloy, cyclically oxidized at 1150 degrees C for 2000 hr. One sample exhibited accentuated coating grain boundary wrinkling, initiating local alumina scale spallation to bare metal, resulting in a final weight loss of 3.3 milligrams/(square centimeter). Spallation under ambient conditions was monitored with time after cooldown and was found to continue for times up to 24 hr, ... |
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| Anisotropy of the Hot Plastic Deformation of Ti-6Al-4V Single-Colony Samples (Preprint) |
Apr-2009 |
26 pages |
| Authors:
S L Semiatin; A A Salem; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
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| The critical resolved shear stresses and flow curves for the seven possible slip systems in Ti-6Al-4V with a lamellar microstructure were determined via high temperature uniaxial compression testing. For this purpose, samples with a rectangular cross section were cut from single colonies grown using a float-zone technique and then tested at 815 degrees C. Each sample was oriented for single slip along one of seven different slip systems in the ... |
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| Application of a Ternary Phase-Field Model to Precipitation Behavior in Ni-Al-Cr Alloys (Preprint) |
Apr-2009 |
22 pages |
| Authors:
J P Simmons; C Woodward; Y H Wen; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
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| A recently developed ternary phase-field model is applied to study the precipitation behavior in Ni-Al-Cr alloys. The effect of diffusivity and initial compositional/ordering profiles on the growth process of precipitates are examined. Specifically, the composition evolution with time in the precipitates is simulated and compared with experimental observations by Sudbrack et al. The simulation work reveals that the CR- trapping phenomenon can only be reproduced with no significant partitioning of ... |
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| Thermal Analysis of the Effect of Oxygen Contamination on Undercooling of Zr-Al-Ni-Cu, Cu-Zr-Ti, and Cu-Ni-Zr-Ti Metallic Glasses (Preprint) |
Apr-2009 |
24 pages |
| Authors:
D B Miracle; W S Sanders; S A Firdosy; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
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| Oxygen impurity levels have been varied in Zr65Al7.5(Cu17.5Ni10), Cu60Zr30Ti10, and (Cu47Ni8)Zr11Ti34 glass forming alloys, and their effect has been characterized by differential scanning calorimetry and x-ray diffraction. Results indicate that these alloys exhibit varying amounts of sensitivity to oxygen. In Zr65A17.5(Cu17.5Ni10)change in Tx decreases dramatically from over 100K to 55K when 1.0 at% oxygen is added; in (Cu47Ni8)Zr11Ti34, change in Tx remains relatively constant at 45K up to 1.2 at% ... |
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| Multi-Scale Characterization of Inhomogeneous Morphologically Textured Microstructures (Preprint) |
Apr-2009 |
9 pages |
| Authors:
J E Spowart; G B Wilks; M A Tschopp; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
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| A computationally efficient microstructure characterization technique is presented that separately identifies morphological texture and any orientation dependence of second-phase clustering via a concise visual representation. This technique, the Vector Multi-Scale Analysis of Area Fractions (VMSAAF), is then applied to computer-generated microstructures to understand the effects of second-phase area fraction, aspect ratio, alignment propensity, variant orientation, and degree of microstructure banding on the homogenous length scale- a metric used to quantify ... |
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| Low-Temperature Superplasticity of Ultra-Fine-Grained Ti-6Al-2Sn-4Zr-2Mo-0.1Si Alloy |
31-Mar-2009 |
41 pages |
| Authors:
Chan H Park; Chong S Lee; POHANG UNIV OF SCIENCE AND TECHNOLOGY (SOUTH KOREA)
|
| This study aimed to achieve low-temperature superplasticity of Ti-6Al-2Sn-4Zr-2Mo-0.1Si alloy utilizing dynamic globularization, and to elucidate the deformation mechanisms in the context of inelastic-deformation theory. The as-received microstructure with equiaxed-alpha grain/particle size of 13microneters was refined to 2.2 micronmeters by dynamic globularization at 775 C, which was confirmed by electron back-scattered diffraction (EBSD) analysis. Uniaxial tension tests were carried out for both coarse (starting material) and fine (dynamically globularized materials) ... |
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| Study of Load Transfer and Fracture on Composite-to-Metal-Wire Joints |
01-Mar-2009 |
60 pages |
| Authors:
Mark F Boseman; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| In order to connect a composite structure to a metallic structure, a hybrid composite/metal-wire laminate has been considered. Such a hybrid laminate raises a question of interface strength between the composite layer and metal-wire layer, and what kind of lay-up configuration would be the best. In order to answer the question, the following three joints were considered: butt joint, overlap joint, and modified-wire-end-shape joint. The goal of this research was ... |
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| Separation of Depleted Uranium From Soil |
Mar-2009 |
197 pages |
| Authors:
Steven Larson; Victor Medina; John Ballard; Michelle Thompson; Greg O'Connor; Chris Griggs; Catherine Nestler; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS ENVIRONMENTAL LAB
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| Dry and wet physical separation processes were tested at Yuma Proving Ground to remove depleted uranium (DU) from soil. Four sample locations were tested that had varied uranium concentration, weathering, and aging of fired, DU residues. Reduction of soil DU concentration was achieved using simple vibratory or agitated screening techniques. For soils into which the DU had been recently fired, these techniques were successful at removing a large fraction (70 ... |
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| Effects of Contact Load on the Fretting Fatigue Behavior of IN-100 at Elevated Temperature |
Mar-2009 |
173 pages |
| Authors:
Traylor; Alfred G II; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
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| This thesis studied the effects of contact load of 8006 N on the fretting fatigue behavior of IN-100 at an elevated temperature of 600 deg C. First, S-N curves were created for a range of applied axial stresses at an identical stress ratio of 0.03 at 8006 N. A condition of partial slip condition necessary to fretting fatigue was verified by generating hysteresis loops, plotting shear force against axial stress. ... |
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| Carcinogenicity of Embedded Tungsten Alloys in Mice |
Mar-2009 |
27 pages |
| Authors:
John F Kalinich; JACKSON (HENRY M) FOUNDATION FOR THE ADVANCEMENT OF MILITARY MEDICINE ROCKVILLE MD
|
| A variety of unique metal mixtures have entered the military arsenals of many countries in recent years. One such material is the tungsten alloys, which have been proposed as replacements for depleted uranium (DU) in armor-penetrating munitions. As a result, opportunities for exposure are increasingly likely. This leads to questions, similar to those originally surrounding DU, as to the health effects of exposure to the tungsten alloys, especially for embedded ... |
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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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| Microstructural Evolution and Tensile Properties of SnAgCu Mixed with Sn-Pb Solder Alloys (Preprint) |
Mar-2009 |
23 pages |
| Authors:
Fengjiang Wang; Matthew O'Keefe; Brandon Brinkmeyer; MISSOURI UNIV-ROLLA
|
| The effect of incorporating eutectic Sn-Pb solder with Sn-3.0Ag-0.5Cu (SAC 305) Pb-free solder on the microstructure and tensile properties of the mixed alloys was investigated. Alloys containing 100, 75, 50, 25, 20, 15, 10, 5 and 0 wt. % SAC 305, with the balance being Sn-37Pb eutectic solder alloy, were prepared and characterized. Optical and scanning electron microscopy were used to analyze the microstructures while mini-tensile test specimens were fabricated ... |
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| Elemental Partitioning Associated with Different Generations of Gamma Prime Precipitates in Rene 88DT Nickel Base Superalloy (Preprint) |
Mar-2009 |
28 pages |
| Authors:
J Tiley; J Y Hwang; R Banerjee; R Srinivasan; G B Viswanathan; H L Fraser; S Nag; NORTH TEXAS STATE UNIV DENTON
|
| The compositional and microstructural evolution of different generations of precipitates of the ordered gamma-prime 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 tomography (3DAP) coupled with energy-filtered transmission electron microscopy studies. After solutionizing in the single gamma phase field, during continuous cooling at a relatively slow rate (approx. 24 degrees C/min), the first ... |
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| Microstructure-Sensitive Extreme Value Probabilities for High Cycle Fatigue of Ni-Base Superalloy IN100 (Preprint) |
Mar-2009 |
48 pages |
| Authors:
Craig P Przybyla; David L McDowell; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
|
| To quantify the effects of interactions between various microstructure attributes on fatigue life in the high cycle fatigue (HCF) regime, we have proposed a new microstructure-sensitive extreme value statistical framework. This framework couples the extreme value distributions of certain fatigue indicator parameters (FIPs) or response functions to the correlated microstructure attributes that exist at the extreme value locations of these FIPs. We demonstrate the application of this statistical framework to ... |
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| Development of Methods for the Quantification of Microstructural Features in Alpha+Beta Processed Alpha/Beta Titanium Alloys (Preprint) |
Mar-2009 |
22 pages |
| Authors:
J Tiley; H L Fraser; P C Collins; B Welk; T Searles; J C Russ; NORTH TEXAS STATE UNIV DENTON
|
| A set of stereological procedures has been developed for the rigorous quantification of microstructural features resolvable using scanning electron microscopy in alpha+beta processed alpha/beta titanium alloys. This paper identifies the four microstructural features that most likely influence the mechanical properties in alpha+beta processed titanium alloy, including: the size of the equiaxed alpha, the volume fraction of the equiaxed alpha, the volume fraction of total alpha, and the thickness of the ... |
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| NbTiSiMo-X Alloys-Composition, Microstructure Refinement and Properties (Preprint) |
Mar-2009 |
15 pages |
| Authors:
C Woodward; Y-W Kim; S Menon; UES INC DAYTON OH
|
| Advanced NbTiSi-X alloys have demonstrated very high RT strength levels (compressive yield strength approaching 1,800 MPa) and excellent high-temperature strength retention (approx. 1,200 MPa at 1,000 degrees C and over 500 MPa at 1,200 degrees C). Unfortunately, these alloys have an inhomogeneous size and spatial distribution of silicides, low fracture strength under tension (300 MPa) at all temperatures, and low oxidation resistance. The high volume fraction and non-uniform size distribution ... |
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| Evolution of the gamma/gamma' Interface Width in a Commercial Nickel Base Superalloy Studied by 3D Atom Probe (Preprint) |
Mar-2009 |
15 pages |
| Authors:
J Tiley; J Y Hwang; R Banerjee; R Srinivasan; H L Fraser; S Nag; A R Singh; NORTH TEXAS STATE UNIV DENTON
|
| The compositional width of the gamma/gamma-prime interface for primary and secondary gamma-prime precipitates in the commercial nickel base superalloy, Rene 88 DT, has been characterized at sub-nanometer resolution using local electrode atom probe (LEAP) tomography. On formation during continuous cooling, the primary gamma-prime precipitates exhibit a very sharp interface while the secondary gamma-prime precipitates exhibit a substantially more diffuse interface. Interestingly, on subsequent isothermal aging at 760 degrees C, the ... |
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| Terahertz Generation in GaN/AlGaN Superlattices |
28 Feb 2009 |
32 pages |
| Authors:
Hadis Morkoc; VIRGINIA COMMONWEALTH UNIV RICHMOND
|
| Nitride semiconductors based heterostructures have so far been exploited for electronic devices utilizing transport parallel to heterointerfaces. However, the vertical transport and its understanding in this heterostructure system are nascent. Heterojunction bipolar transistors have fundamental problems having to do with low base p-doping in terms of bipolar transistor standards and inferior emitter quality because of the poor quality Mg doped underlying base layer. The PnP variety is even worse. In ... |
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| Spider Silk Spun and Integrated into Composites |
20-Feb-2009 |
15 pages |
| Authors:
Fritz Vollrath; OXFORD UNIV (UNITED KINGDOM)
|
| We gained significant new insights into the role of hydration for silks with our data allowing us to model in considerable detail the interaction between silk molecules and water. Our fibre and feedstock experiments demonstrated that the hierachical morphology in the patterning and mesophase assembly is spatially optimised. Our multiscale model, based on experimental data collected iteratively and focussing on the control of energy storage (strength) and dissipation (toughness) at ... |
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| Aircraft Steels |
19-Feb-2009 |
46 pages |
| Authors:
R Taylor; E U Lee; C Lei; H C Sander; NAVAL AIR WARFARE CENTER AIRCRAFT DIV PATUXENT RIVER MD
|
| Five high strength steels (4340, 300M, AerMet 100, Ferrium S53, and Hy-Tuf) and four stainless steels (High Nitrogen, 13-8Mo, Custom 465, and MLX17) have been evaluated with respect to their characteristics and applicability to the current and future Navy aircraft. In this endeavor, their metallurgical feature, mechanical property, fatigue behavior, and corrosion resistance have been investigated and compared. |
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| Air Force Corrosion Prevention and Control Office (AFCPCO) |
06-Feb-2009 |
36 pages |
| Authors:
Kimberly Andrews; AIR FORCE CORROSION PREVENTION AND CONTROL OFFICE ROBINS AFB GA
|
| These briefing charts discusss the mission and people connected with the Air Force Corrosion Prevention and Control Office (AFCPO), its accomplishments, current efforts, projects and future plans. |
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| Corrosion Mitigation Strategies - an Introduction |
05-Feb-2009 |
72 pages |
| Authors:
Joe Curran; NATIONAL ASSOCIATION OF CORROSION ENGINEERS HOUSTON TX
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| METHODS OF CORROSION CONTROL -- SUMMARY: Design * Materials Selection * Protective Coatings * Cathodic Protection * Modification of Environment. |
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| Corrosion Inhibiting Chromate-Free Nanocomposite Pretreatments and Nanoparticle Primer Additives for Structural Metals |
05-Feb-2009 |
26 pages |
| Authors:
Fred Allen; NEI CORP SOMERSET NJ
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| NEI Corporation Spins Out American NanoMyte (Formerly NEI Corrosion Technologies): Experience in developing, manufacturing and distributing nanoscale materials for a broad range of customers around the world * Expertise in nanoparticle synthesis, surface modification and coatings, and nanotechnology-based formulations * Nanomyte line of products, developed by creating nanostructures and modifying them through novel chemistry, fall into two broad categories: ADDITIVES -- Nanomaterials tailored to meet the specific performance and manufacturing ... |
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| Naval Aviation Enterprise Corrosion Prevention Team |
05-Feb-2009 |
26 pages |
| Authors:
NAVAL AIR SYSTEMS COMMAND WASHINGTON DC
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| SUMMARY: Corrosion is a significant cost to the Navy -- NAVAIR's total annual budget is $40B; annual corrosion cost is estimated $3.0B * The Naval Aviation Enterprise Corrosion Prevention Team is attacking corrosion problems in all phases of aircraft life cycle * Solutions lie in the areas of leadership, training, policy, basing, materials, design, and documentation. |
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| Galvanic Corrosion Study on SS Cartridge Design |
05-Feb-2009 |
24 pages |
| Authors:
Daniel P Schmidt; ARMY RESEARCH DEVELOPMENT AND ENGINEERING COMMAND ABERDEEN PROVING GROUND MD
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| BACKGROUND: Lightweight Cartridge for Small Arms program at Picatinny -- Designing/developing stainless steel cartridge case -- For structural support inserting Al plug * Galvanic corrosion -- Dissimilar metals that are in electrical contact while immersed in a solution electrolyte * 3 main galvanic couples of concern. OBJECTIVE: To investigate the galvanic interaction between the materials used in the new ammunition design under aggressive conditions to determine if there will be ... |
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| Plasma-Based Surface Modification and Corrosion in High Temperature Environments |
05-Feb-2009 |
19 pages |
| Authors:
Todd Allen; Lizhen Tan; Kumar Sridharan; WISCONSIN UNIV-MADISON
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| * Corrosion research at the University of Wisconsin is focused on two areas (i) plasma-based surface treatments to reduce corrosion, (ii) high temperature corrosion in harsh environments. * Plasma-based surface treatments (10 to 2000nm depth) have involved ion implantation and thin film deposition and atomic mixing approaches to mitigate corrosion and wear. * Specific testing equipment for corrosion testing in high temperatures and harsh environments such as supercritical water, molten ... |
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Properties of Metals and Alloys
