| Technical Operations Support III (TOPS III). Task Order 0061: Fundamental Theory Based Assessment of Thermoelectric Merit Factor for Heusler Alloys |
OCT 2010 |
29 pages |
| Authors:
Alper Kinaci; Shiv Meka; Cem Sevik; Tahir Cagin; TEXAS A AND M UNIV COLLEGE STATION
|
 | Intensive previous work (1950-1970) led to discovery of bulk Bi2Te3 and Sb2Te3 type heavy metal, low temperature thermoelectrics having dimensionless figure of merits (ZT's) in the vicinity of 1. Nonetheless, no material having marginally higher performance over Bi-Te and Sb-Te thermoelectrics can yet be commercialized. Moreover, these materials are not very practical due to scarcity of the elements, toxicity and decomposition-evaporation problems at elevated temperatures. Today, there are a number ... |
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| Fundamental Electronic Structure Characteristics and Mechanical Behavior of Aerospace Materials |
APR 2008 |
22 pages |
| Authors:
Arthur J. Freeman; Oleg Y. Kontsevoi; Yuri N. Gornostyrev; Nadezhda I. Medvedeva; NORTHWESTERN UNIV EVANSTON IL DEPT OF PHYSICS AND ASTRONOMY
|
| To fulfill the great potential of intermetallic alloys for high temperature structural applications, it is essential to understand the mechanisms controlling their mechanical behavior on the microscopic level. We focus on the mechanical behavior of homogeneous intermetallics with LI 2 and B2 structures, two-phase `ly' alloys, and bcc transition metals and their alloys. Based on highly-accurate total energy calculations and large-scale Peierls-Nabarro and atomistic modeling, we investigated the relation between ... |
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| Unlubricated Gross Slip Fretting Wear of Metallic Plasma Sprayed Coatings for Ti6A14V Surfaces |
NOV 2006 |
37 pages |
| Authors:
Jr. Hager Carl H.; Jeffrey H. Sanders; Shashi K. Sharma; UNIVERSAL TECHNOLOGY CORP DAYTON OH
|
| Plasma sprayed Al-bronze (Al-Br) or CuNiIn coatings are often applied to protect against fretting wear and extend the operational life of Ti-alloy compressor blades in turbine engines. In order to develop a fundamental understanding of how these coating systems perform under gross slip fretting conditions, bench level fretting wear tests were conducted at room temperature to simulate cold engine startup. Alternative coatings such as plasma sprayed molybdenum and nickel were ... |
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| Fatigue Response of Mo-Si-B Alloys |
SEP 2005 |
77 pages |
| Authors:
K. S. Kumar; BROWN UNIV PROVIDENCE RI DIV OF ENGINEERING
|
| The high-temperature compression response as well as the monotonic and cyclic crack growth behavior of a two-phase Mo-Si-B alloy compared to a TZM alloy. The compression studies confirmed that deformation in the temperature-strain rate space evaluated is matrix-dominated. In all instances evaluated, the Mo-Si-B alloys is superior to TZM. Fracture toughness of the Mo-Si-B alloy increases from ^8MPa x m at room temperature to ^25 MPa x m at l400C, ... |
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| Phase Stability and Microstructure Control in High Temperature (Mo,Nb)- Si-B Alloys |
04 JAN 2003 |
31 pages |
| Authors:
John H. Perepezko; WISCONSIN UNIV-MADISON OFFICE OF RESEARCH ADMINISTRATION
|
| The challenges of a high temperature environment (T>14O0 C) impose severe material performance constraints in terms of melting point, oxidation resistance and structural functionality. A number of ceramic materials, intermetallic compounds and refractory metals with high melting temperature are available as material choices. However, in a single component, single phase form, these materials rarely satisfy all the above requirements because of the brittleness of ceramic materials and intermetallic compounds at ... |
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| Refractory Alloy Single Crystals for High Temperature Applications |
01 DEC 2000 |
61 pages |
| Authors:
Ralph H. Zee; William F. Gale; AUBURN UNIV AL DEPT OF MECHANICAL ENGINEERING
|
| Refractory metals and intermetallic alloys are important in high temperature aerospace systems where deformation must be maintained at a low level. This DEPSCoR project was devoted to the processing such single crystals, joining of these crystals and fracture analysis of the interface. Advances have been made in these three areas, especially in the processing of single crystals with enhanced mechanical properties. An electron beam float zone melting method was used ... |
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| Phase Stability and Microstructural Design in High Temperature (Mo,Nb)- Si-B Alloys |
15 OCT 1999 |
62 pages |
| Authors:
John H. Perepezko; WISCONSIN UNIV-MADISON DEPT OF MATERIALS SCIENCE AND ENGINEERING
|
| The challenges of a high-temperature (T> 1400 deg C) environment impose severe constraints on materials selection in terms of melting temperature, oxidation resistance and structural functionality. In order to satisfy these criteria refractory metal silicides that can develop adherent SiO2 oxidation layers emerge as the most attractive candidates However, multiphase microstructure designs must be applied to address the toughening and strengthening issue that must be resolved for the use of ... |
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| Dynamic Failure of Materials. Volume 2 - Compilation of Russian Spall Data |
01 NOV 1998 |
162 pages |
| Authors:
Tarabay H. Antoun; Lynn Seaman; Donald R. Curran; SRI INTERNATIONAL MENLO PARK CA
|
| Over the past three decades, scientist in the Former Soviet Union (FSU) and in the West have developed innovative experimental techniques, measurement diagnostics, and constitutive models of the Spall Process. Extensive literature has been built up over the years in Western publications. However, much of the FSU work was not available in English and was largely inaccessible to Western readers. Improved communication between Western and FSU scientists since the end ... |
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| Materials Processing and Microstructure Control in High Temperature Ordered Intermetallics |
16 JUN 1997 |
74 pages |
| Authors:
J. H. Perepezko; WISCONSIN UNIV-MADISON DEPT OF MATERIALS SCIENCE AND ENGINEERING
|
| In the development of high temperature intermetallic systems for structural applications a crucial issue is the formulation of materials processing strategies in order to achieve controlled microstructures that are designed to provide for the required mechanical performance. In the current research an integrated approach that couples processing with microstructure control as guided by the operative phase equilibria has been used to identify several promising intermetallic alloys. The experimental efforts have ... |
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| Intermetallic Matrix Composites via in-situ Displacement Reactions |
JUN 97 |
11 pages |
| Authors:
Michael Kaufman; FLORIDA UNIV GAINESVILLE DEPT OF MATERIALS SCIENCE AND ENGINEERING
|
| Among the obstacles encountered in the development of intermetallic matrix composites are (1) the thermodynamic and mechanical incompatibility between the matrix and reinforcement phases and (2) the matrix reinforcement interfacial properties which are not ideal from the standpoint of achieving optimum properties in the composite as a whole. In the past, the first of these problems has been addressed by coating the reinforcements with some sort of barrier or compliant ... |
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| Part I. The Effect of Dissolved Ozone on the Corrosion Behavior of Stainless Steels in Artificial Seawater. Part II. The Effect of Dissolved Ozone on the Corrosion Behavior of Ni-Cr-Mo Alloys in Artificial Seawater |
JAN 97 |
|
| Authors:
W. E. Wyllie Ii; D. J. Duquette; B. E. Brown; RENSSELAER POLYTECHNIC INST TROY NY
|
 | The corrosion resistance of austenitic stainless steels in artificial seawater containing 0.2 to 0.4 mg/L dissolved ozone was investigated. According to cyclic polarization data, UNS S30400 and S31600 stainless steels are resistant to pit initiation after 8 weeks exposure to ozonated artificial seawater. However, if crevices exist, crevice corrosion is more severe in ozonated vs. aerated artificial seawater. Maximum crevice corrosion penetration rates of 8 and 5 mm/y were recorded ... |
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| Enhancement of Corrosion Resistance and Mechanical Properties of Light- Weight Metals Through the Use of Graded Nonequilibrium Microstructures. |
22 DEC 1995 |
65 pages |
| Authors:
Barbara Shaw; Kelly Kennedy; Kirk Scammon; Ed Principe; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF ENGINEERING SCIENCE AND MECHA NICS
|
| Designs for the future will place extreme demands on light-weight materials. In order to meet these future challenges, it is vital that an emphasis be placed on tailor-making materials with enhanced specific properties. Through the use of rapid solidification processing, advances have been made in our ability to engineer materials -- but we have yet to be able to tailor-make a light-weight alloy with all of the characteristics we desire. ... |
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| Shock Synthesis of Materials Workshop Held in Atlanta, Georgia on May 24-26, 1995 |
08 SEP 95 |
536 pages |
| Authors:
Naresh Thadhana; Edward Chen; GEORGIA INST OF TECH ATLANTA
|
| Synthesis of materials by shock-induced chemical reactions (shock chemistry) has in recent years, evolved from the stage of curiosity-driven and proof-of-concept experiments, to the need for developing a fundamental understanding of this unique but complex process. The unusual combination of pressure and temperature states that produce the large plastic deformations, are only singularly possible during shock-compression. Shock chemistry can, thus, be applied for synthesis of metastable phases, non-stoichiometric compounds, and ... |
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| Reaction Kinetics of Mo(a(7)S3, a(5)D4, a(5)S2) with CO2, N2O, SO2, and NO |
09 MAY 95 |
38 pages |
| Authors:
Robert H. Goodwin; NAVAL ACADEMY ANNAPOLIS MD
|
| The gas phase reactivities of Mo(a(7)S3, a5Dj, a(5)S2) with CO2, NO, SO2, and N2O were measured under pseudo-first order conditions (Mo< |
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| High Temperature X-Ray Diffractometer for Advanced Materials Research |
25 FEB 95 |
18 pages |
| Authors:
Shankar M. Sastry; William E. Buhro; WASHINGTON UNIV ST LOUIS MO
|
| The X-ray diffractometer system purchased under the grant consists of an X-ray generator and associated equipment for determination of degree of crystallinity, crystallite size and lattice distortion in nano-and micro- crystalline metals and composites; identification of crystalline phases, precision measurement of lattice constants, and determination of phase transformation temperatures in metals, ceramics, and composites at 25-1400 degrees Celsius; determination of grain orientations, preferred orientation, and crystallographic texture by Laue back ... |
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| Nonequilibrium Alloying of Aluminum for Improving the Corrosion Resistance of Graphite-Reinforced Metal Matrix Composites |
JUN 94 |
15 pages |
| Authors:
Barbara A. Shaw; Tia R. Schrecengost; Paul L. Miller; Robert G. Wendt; William C. Moshier; PENNSYLVANIA STATE UNIV UNIVERSITY PARK
|
| High modulus graphite (Gr) reinforced metal matrix composites (MMCs) offer a wide variety of attractive properties including: high specific modulus and strength (E/p and UTS/p), tailorable or zero coefficient of thermal expansion (CTE), and high thermal conductivity. Using Al as the matrix metal results in a reduction of the final density of the composite with high elastic modulus and excellent strength in the fiber direction. Unfortunately, MMCs, especially Gr reinforced ... |
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| Chromium/Molybdenum Alloy Plating. Part 1: The Electrodeposition of Low Contraction Chromium/Molybdenum Alloys Using Unipolar (On/Off) Pulse Plating |
MAR 94 |
19 pages |
| Authors:
Mark D. Miller; Stephen Langston; ARMY ARMAMENT RESEARCH DEVELOPMENT AND ENGINEERING CENTER WATERVLIET NY BENET LABS
|
| The microstructure and mechanical properties of a pulse-plated low contraction (LC) chromium/molybdenum (Cr/Mo) alloy deposit were evaluated and compared to both pulse-plated LC chromium and direct (dc)-plated LC chromium. Molybdenum concentrations as high as approximately 2.4 percent were obtained at a pulsing frequency of 5 Hz (100 ms on-time/100 ms off-time). This represents nearly a 300 percent increase over the percent molybdenum obtained in a dc- plated LC Cr/Mo alloy ... |
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| Symposium on Structural Intermetallics: Perspectives on Science and Technology Held in Hyderabad, India on 5-6 February 1994. Volume 2 |
06 FEB 94 |
194 pages |
| Authors:
MATERIALS RESEARCH SOCIETY OF INDIA NEW DELHI
|
| Contents include: (1) European intermetallics activities and contribution from France; (2) Microstructure processing and properties of MoSi2; (3) Effect of Microstructure on the creep of molybdenum disilicides and their composites; (4) Ordered ground state structures in HCP alloys; and (5) Stability |
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| Field-Emitter Arrays for RF Vacuum Microelectronics |
20 OCT 93 |
21 pages |
| Authors:
C. A. Spindt; C. E. Holland; P. R. Schwoebel; SRI INTERNATIONAL MENLO PARK CA
|
| SRI International has completed the eighth quarter of a program to develop field-emitter arrays for vacuum microelectronics. We have met the first- phase program goals of 5 mA total emission, with a current density of 5 A/sq. cm for at least 2 hours and demonstrated modulation of the emission current at a frequency of 1 GHz. A two-step reactive-ion-etch process was established to eliminate an earlier problem with sulfur contamination ... |
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| Solidification Processing and Phase Transformations in Ordered High Temperature Alloys |
20 JAN 93 |
205 pages |
| Authors:
William J. Boettinger; Leonid A. Bendersky; Ursula R. Kattner; NATIONAL INST OF STANDARDS AND TECHNOLOGY GAITHERSBURG MD METAL- LURGY DIV
|
| Useful high temperature alloys generally have microstructures consisting of more than one phase. Multiphase microstructures are necessary to develop acceptable toughness and creep strength in high temperature intermetallic alloy matrices. The optimum microstructures must be developed by a careful selection of processing path that includes both solidification and solid state heat treatment. Research has been conducted on the rapid solidification of selected intermetallic alloys and on the phase transformation paths ... |
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| SiC Particles Beef Up Investment-Cast Aluminum. |
JUN 1991 |
|
| Authors:
D. O. Kennedy
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|
| Whither Advanced Materials? |
JUN 1991 |
|
| Authors:
T. W. Eager
|
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| Experimental Evaluation of New Alloy Coatings |
19 JUL 89 |
51 pages |
| Authors:
Kang N. Lee; Wayne L. Worrell; PENNSYLVANIA UNIV PHILADELPHIA DEPT OF MATERIALS SCIENCE AND ENGINEERING
|
| The oxidation behavior of binary iridium aluminum and iridium and hafnium alloys, and ternary iridium aluminum-silicon, rhenium aluminum silicon, tungsten aluminum-silicon and molybdenum aluminum silicon alloys has been investigated in 1 atm oxygen at 1550 C - 1800 C. Iridium-hafnium alloys form a protective hafnia scale at above 50 at % hafnium and iridium-aluminum alloys form a protective alumina scale at above 55% aluminum. Silicon decreases the aluminum concentration necessary ... |
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| Effect of Microstructure on the Fatigue Crack Propagation Behavior of Ni-Base Superalloys |
DEC 87 |
|
| Authors:
Stephen D. Antolovich; GEORGIA INST OF TECH ATLANTA SCHOOL OF MATERIALS ENGINEERING
|
| The objective of this study is to determine the effect of microstructural properties on the fatigue crack propagation (FCP) response of nickel-base superalloys. This report describes the results of four experimental alloys containing various amounts of Al, Ti, Cr, and Mo. Chemistry, precipitate size, and grain size were varied to produce systematically controlled microstructures. The four alloys were characterized for chemical composition, microstructure, tensile properties, low cycle fatigue (LCF), and ... |
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| A Comparison of High Damping Shape Memory Alloys with Cu-Mn-Based and Fe-Cr-Based Alloys |
JUN 87 |
|
| Authors:
Joseph T. Cronauer; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The strain dependence and temperature dependence of damping in the thermoelastic martensitic (shape memory) alloys titanium-nickel and copper zinc aluminum was compared to predetermined optimum damping behavior in the quiet alloys copper manganese aluminum and iron chromium molybdenum. Damping measurements were taken using a modified resonant dwell technique, in which cantilever beams were evaluated for damping at their first three resonant modes at temperatures between ambient and 110 C. Differential ... |
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| Method for Refining Microstructures of Prealloyed Titanium Powder Compacted Articles. |
07 APR 1987 |
|
| Authors:
Lev Levin; Russell G. Vogt; Daniel Eylon; Francis H. Froes; DEPARTMENT OF THE AIR FORCE WASHINGTON DC
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| In accordance with the present invention there is provided a process for improving the microstructure of a titanium article made by powder metallurgy which comprises, in combination, the steps of: beta-solution heat treating the article for a relatively brief time; quenching the article; hydrogenating the article; and dehydrogenating the article. The method of the present invention comprises beta solution treatment of an article produced by powder metallurgy, followed by hydrogenation/dehydrogenation ... |
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| High Energy High Rate Pulsed Power Processing of Materials by Powder Consolidation and by Railgun Deposition |
31 MAR 87 |
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| Authors:
C. Persad; H. L. Marcus; W. F. Weldon; TEXAS UNIV AT AUSTIN CENTER FOR MATERIALS SCIENCE AND ENGINEERING
|
| This exploratory research program was initiated to investigate the potential of using pulse power sources for powder consolidation, deposition and other High Energy High Rate Processing. The characteristics of the High Energy High Rate (1MJ/s) powder consolidation using megampere current pulses from a Homopolar Generator, have been defined. Molybdenum Alloy TZM, A Nickel based metallic glass, Copper graphite composites, and P/M Aluminum Alloy X7091 have been investigated. The powder consolidation ... |
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| Al and Mg Alloys for Aerospace Applications Using Rapid Solidification and Powder Metallurgy Processing |
14 NOV 86 |
|
| Authors:
Hamish L. Fraser; ILLINOIS UNIV AT URBANA DEPT OF MATERIALS SCIENCE
|
| This report covers the progress made in the first year of a three year study on the rapid solidification processing (RSP) of Al-and Mg based alloys. In this study, effort has been applied in three areas: (1) Processing (both particulate production and consolidation), 2) Microstructural effects, and (3) Mechanical Properties. The underlying objective has been to control the microstructure to obtain favorable mechanical properties. This will, perforce, entail a detailed ... |
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| Synthesis and Properties of Elevated Temperature P/M Aluminum Alloys |
30 NOV 85 |
|
| Authors:
Morris E. Fine; Julia R. Weertman; NORTHWESTERN UNIV EVANSTON IL DEPT OF MATERIALS SCIENCE AND ENGINEERING
|
| The microstructure of the aluminum base-iron-cerium and iron- molybdenum-vanadium alloys, which were developed for use up to 316 degrees centigrade, is not stable at 425 degrees centigrade (three-quarters of the absolute melting temperature of aluminum). Metastable dispersed phases are replaced by stable phases and particles of these coarsen rather rapidly with time. Creep loading accelerates these processes. Trialuminum-zirconium was predicted to be a preferable dispersed phase for strengthening aluminum for ... |
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| Mechanisms and Kinetics of Surface Alloying by Diffusion-Induced Grain Boundary Migration |
SEP 85 |
|
| Authors:
J. R. Manning; J. W. Cahn; D. B. Butrymowicz; C. A. Handwerker; NATIONAL BUREAU OF STANDARDS GAITHERSBURG MD METALLURGY DIV
|
| The recently recognized phenomenon of diffusion-induced grain boundary migration has been systematically investigated to determine conditions under which this effect occurs and to establish the mechanism and driving forces that control this process. This migration and the surface alloying that accompanies it were observed in a number of different alloy systems, including Cu-Zn, Cu-As, Au-Pd, Fe-Zn, Fe-Cr, and Fe-As. Detailed tests in the Ag-Au alloy system using thin layers of ... |
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| The Densification of Molybdenum and Molybdenum Alloy Powders Using Hot Isostatic Pressing |
AUG 85 |
|
| Authors:
J. Barranco; I. Ahmad; S. Isserow; R. Warenchak; ARMY ARMAMENT RESEARCH AND DEVELOPMENT CENTER WATERVLIET NY LARGE CALIBER WEAPON SYSTEMS LAB
|
| This study was conducted to determine a superior erosion resistant gun barrel liner material with improved properties at higher temperatures. Four categories of powders were examined: 1. TZM spherical containing 0.5 titanium, 0.08 zirconium, and 0.02 carbon (wt. % nominally), balance molybdenum (Mo), produced by REP (Rotating Electrode Process), PREP (Plasma Rotating Electrode Process), and PMRS (Plasma Melted and Rapidly Solidified); 2. Mo reduced 2 and 5 microns; 3. Mo-0.1% ... |
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| New Powder Technologies for Molybdenum Alloy Gun Barrel Liners |
JUN 85 |
42 pages |
| Authors:
J. M. Barranco; S. Isserow; ARMY ARMAMENT RESEARCH AND DEVELOPMENT CENTER WATERVLIET NY LARGE CALIBER WEAPON SYSTEMS LAB
|
| Molybdenum is an attractive material for resisting gun barrel erosion because of its high melting point and mechanical properties. In previous efforts, molybdenum has been unsatisfactory because of the coarse grains and strong anisotropy in conventionally processed material. Powder metallurgy offers the opportunity to overcome these deficiencies. New technologies for preparing and consolidating powders are therefore being investigated to permit utilization of the benefits of molybdenum for this and related ... |
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| Fatigue Behavior of HY-130 Steel Weldments Containing Fabrication Discontinuities |
18 APR 85 |
|
| Authors:
S. J. Gill; J. A. Hauser Ii; T. W. Crooker; B. J. Kruse; R. Menon; NAVAL RESEARCH LAB WASHINGTON DC
|
| Fabrication discontinuities in weldments pose a serious engineering problem for structural applications involving cyclic loading. Often, the discovery of fabrication discontinuities through nondestructive inspection can pose a dilemma; if not properly repaired, failure can result from crack initiation and growth, however, if improperly repaired, post-repair discontinuities of even greater severity may result. Thus, a need exists for rational decision-making criteria to assess the mechanical severity of actual fabrication defects in ... |
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| Synthesis and Properties of Elevated Temperature P/M Aluminum Alloys |
30 NOV 84 |
|
| Authors:
M. E. Fine; J. R. Weertman; NORTHWESTERN UNIV EVANSTON IL DEPT OF MATERIALS SCIENCE AND ENGINEERING
|
| The dispersed phases in the Al-8Fe, Al-10Fe-1.5Mo-1V, Al-8.8Fe-3.7Ce and Al-8.9Fe-6.9Ce RSP P/M alloys have been examined for composition and coarsening rate. Additionally, effects of prior heat treatment and deformation on particle coarsening have been studied. Energy dispersive spectroscopy on extracted particles from the Al-8Fe and Al-10Fe-1.5Mo-1V alloys in the as- received condition as well as after aging at 316 C indicated that the particles have compositions close to Al6Fe. In ... |
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| Microstructural Development and Control in Liquid Phase Sintering; Processing, Structures and Properties of Cold Worked Metal Matrix Composites |
03 JUN 1984 |
24 pages |
| Authors:
T. H. Courtney; J. K. Lee; MICHIGAN TECHNOLOGICAL UNIV HOUGHTON
|
| This report summarizes efforts and accomplishments in the areas noted in the title. Structural analysis of Liquid Phase Sintering materials is clarified in terms of solid phase contiguity and scale; the later being predictively so. Mechanisms for structural evolution in LPS products are also explained. Mechanical processing capabilities of in situ metal matrix composites are developed and the properties obtained in them are measured and compared with theories for the ... |
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| Erosion Mechanisms of Metals |
MAR 1984 |
|
| Authors:
M. E. Gulden; K. G. Kubarych; SOLAR TURBINES INC SAN DIEGO CA
|
| This final report summarizes the experimental approach was to initially study a single alloy which exhibits a transition from brittle to ductile type erosion response at room temperature. At a later stage, the dynamic hardness of several substrate materials, both pure metals and alloys, was measured in order to provide a material property obtained under dynamic conditions similar to those during an actual erosion event. The results can be conveniently ... |
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| Fabricability of and Microstructural Development in Cold Worked Metal Matrix Composites |
84 |
|
| Authors:
P. D. Funkenbusch; T. H. Courtney; D. G. Kubisch; MICHIGAN TECHNOLOGICAL UNIV HOUGHTON DEPT OF METALLURGICAL ENGINEERING
|
| Several processing schemes for metal matrix composites are described. Several unique combinations (Copper/Chromium, Copper/Molybdenum, Nickel/ Tungsten) of metals can be initially processed in such a way that allows them to be subsequently mechanically fabricated into in-situ composites. The structure developed within them is described in terms of initial microstructure and processing employed. Originator-supplied keywords include: Metal Matrix Composites; Processing. ANNOTATION: Reprint: Fabricability of and Microstructural Development in Cold Worked Metal ... |
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| Synthesis and Properties of Elevated Temperature P/M Aluminum Alloys |
29 NOV 1983 |
|
| Authors:
M. E. Fine; J. R. Weertman; NORTHWESTERN UNIV EVANSTON IL DEPT OF MATERIALS SCIENCE AND ENGINEERING
|
| High temperature alloys in order to maintain thier strength during long time exposure at high temperatures must have stable microstructures. The dispersed phase coarsening rates in the A1-7.5Fe-3.5Ce and A1-10Fe-1.5Mo-1V alloys, developed for high temperature applications, were compared at 475 and 575 C. To the extent that the average intercept length cubed, L3, is a linear function of time during isothermal aging, after an initial transient, the particle coarsening obeys ... |
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| Pulsed Electrodeposition of Amorphous and Composite Alloys |
01 SEP 1983 |
|
| Authors:
Rolf Weil; Chin-Chang Nee; STEVENS INST OF TECH HOBOKEN NJ DEPT OF MATERIALS AND METALLURGICAL ENGINEERING
|
| Novel uses of pulsed current in the electrodeposition of alloys were investigated. The study resulted in the demonstration of the feasibility of depositing alternate layers of the same phase or different phases of controlled chemical compositions and thicknesses. The alternate-layer structure resulted in better strength properties in some cases. An orders-of-magnitude increase in the ductility in some layered alloys was discovered. Pulse plating also reduced uncontrolled compositional variations which cause ... |
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| Isothermal and Hot-Die Forging of High-Temperature Alloys |
JUN 1983 |
|
| Authors:
S. L. Semiatin; T. Altan; METALS AND CERAMICS INFORMATION CENTER COLUMBUS OH
|
| Although forging techniques have evolved rather slowly as a metalworking operation, progress has increased in the last 15 years with the introduction of automation and computer-aided design and manufacture (CAD/CAM) methods. In addition, recent developments in isothermal and hot-die forging, in which the dies are heated to the same or about the same temperature as the metals being worked, provide cost-effective alternatives for producing parts from high-temperature alloys. These developments ... |
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| On Fatigue Crack Growth in a Ti-4.5Al-5Mo-1.5Cr Alloy with Metastable Beta-Phase |
10 MAY 1983 |
|
| Authors:
Charles M. Gilmore; George R. Yoder; M. Ashraf Imam; NAVAL RESEARCH LAB WASHINGTON DC
|
| Fatigue crack growth behavior has been examined in a Ti-4.5Al-5Mo-1. 5Cr alloy, for two different levels of beta-phase metastability. The resistance to fatigue crack growth appears to be marginally enhanced with the presence of metastable beta-phase in a microstructure also containing some primary alpha- phase (approx 30 pct) of high aspect ratio. This enhancement appears slightly greater for beta-phase water quenched from 899 deg C, than as more slowly cooled ... |
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| Influence of Container Interactions on the Vaporization Thermodynamics of Nickel |
MAY 1983 |
|
| Authors:
P. L. Mart; MATERIALS RESEARCH LABS ASCOT VALE (AUSTRALIA)
|
| This report describes studies to determine the nature of the interactions between nickel and various refractory containers encountered in high-temperature Knudsen cell vaporization systems. High-temperature mass spectrometric measurements, in conjunction with metallographic studies, were used to determine how these interactions influenced the vaporization thermodynamics of nickel. Such information is essential to permit the determination of valid high-temperature thermodynamic activity data in multi- component alloy systems. |
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| Erosion Resistance Evaluation of Potential Gun Barrel Coatings |
FEB 1983 |
28 pages |
| Authors:
Arthur J. Bracuti; Joseph A. Lannon; Louis A. Bottei; D. Bhat; ARMY ARMAMENT RESEARCH AND DEVELOPMENT CENTER DOVER NJ LARGE CALIBER WEAPONSYSTEMS LAB
|
| The erosion resistance of tungsten/carbon and tantalum/tungsten deposited on AISI 4340 steel and molybdenum substrate were investigated. Erosion data acquired with the ARRADCOM test device indicated poor adhesion between each refractory metal coating and 4340 steel. Mechanical failure of the molybdenum substrate complicated the erosion data, but it was concluded that the tungsten/ carbon coating performed better than steel at higher pressures. No apparent advantage was observed with the tantalum/tungsten ... |
|
| Plasma Accelerator and Energy Conversion Research |
29 OCT 82 |
39 pages |
| Authors:
Eugene V. Pawlik; JET PROPULSION LAB PASADENA CA
|
| The tasks were: 1. To construct by magnetron sputter deposition three AMTEC porous electrodes of 1-3 micron thickness, one of LaB6 on a beta'-alumina solid electrolyte tube, and two of molybdenum-titanium alloy, one of which shall be in the range of 0.2% - 0.5% titanium and the other in the range of 0.5% - 5% titanium. 2. To characterize the morphology and composition of the deposited electrodes before and after ... |
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| Influence of Rare-Earth Additions on Properties of Titanium Alloys. Effects of Yttrium and Erbium Additives on Rapid Solidification Processing, Superplastic Forming, Welding, and Strengthening of Titanium Alloys |
31 JUL 1982 |
|
| Authors:
Shankar M. L. Sastry; T. C. Peng; Richard J. Lederich; James E. O'Neal; MCDONNELL DOUGLAS RESEARCH LABS ST LOUIS MO
|
| Effects of 0.01-2.0 wt% yttrium and erbium additions on rapid solidification processing, superplastic forming, welding, and strengthening of titanium alloys were determined. Ti-8Al-Y and Ti-8Al-Er alloys were rapidly solidified by laser surface melting and electron beam melting and splat- quenching with the objective of simultaneously producing coherent Ti3Al precipitates and incoherent dispersoids. Rapid solidification at cooling rates > 10,000 K/s resulted in 10-100 nm incoherent dispersoids in Ti-8Al-1.5Y and in ... |
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| Shipboard EW Systems. |
MAR 1982 |
|
| Authors:
Harold E. Crecraft; NAVAL RESEARCH LAB WASHINGTON DC
|
|
| High ERP Phased Array ECM Systems. |
MAR 1982 |
|
| Authors:
Murray Simpson; SEDCO SYSTEMS INC MELVILLE NY
|
|
| Higher ERP with Lens Fed Multibeam Arrays. |
MAR 1982 |
|
| Authors:
D. H. Archer; A. A. Black; RAYTHEON CO GOLETA CA ELECTROMAGNETIC SYSTEMS DIV
|
|
| Microprocessor Controls Antitank Skeet. |
MAR 1982 |
|
| Authors:
Philip J. Klass
|
|
| Subsonic and Transonic Roll Damping Measurements on Basic Finner. |
JAN 1982 |
|
| Authors:
H. Sundara Murthy; NATIONAL AERONAUTICAL LAB BANGALORE (INDIA)
|
|
Reports by Keyword(s)
MOLYBDENUM ALLOYS
