A detailed TEM study is reported of the structure of splat-quenched zirconium alloys as follows: Zr-Nb, various compositions; Zr-27at%Al; Zr-14at%Ni; Zr-24at%Fe. The details of martensite and omega morphology in Zr-Nb, spinodal and precipitation reactions in Zr-Al, and the crystallisation of the amorphous phase in Zr-Ni and Zr-Fe are all fully described. In Zr-FE, a novel morphology is described: a circular core of beta surrounded by six twin-related 'petals' of alpha, forms a 'sunflower'...
Topics: DTIC Archive, Banerjee,Srikumar, SUSSEX UNIV BRIGHTON (ENGLAND) SCHOOL OF ENGINEERING AND APPLIED...
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Jul 25, 2010
07/10
by
NON
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The workshop was held to discuss a variety of questions related to the detection and cycling of atmospheric water. Among the questions addressed were: what factors govern the storage and exchange of water between planetary surfaces and atmospheres; what instruments are best suited for the measurement and mapping of atmospheric water; do regolith sources and sinks of water have uniquely identifiable column abundance signatures; what degree of time and spatial resolution in column abundance data...
Topics: ALUMINIDES, TITANIUM CARBIDES, ADDITIVES, GRAVITATIONAL EFFECTS, HEAT RESISTANT ALLOYS, HIGH...
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Jul 11, 2010
07/10
by
YAMAMOTO, A.; TAKAHARA, K.; NOUSE, H.; INOUE, S.; USUI, H.; MIMURA, F
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A SINGLE-STAGE TURBINE WITH A 22 INCH DIAMETER WAS DESIGNED TO INVESTIGATE AIR-COOLED TURBINES OPERATING IN A HIGH-TEMPERATURE ENVIRONMENT. THE STATOR AND ROTOR BLADES ARE CHARACTERIZED BY LOW BLADE SOLIDITY, THICK BLADE SECTION, BLUNT LEADING EDGE AND TRAILING EDGE, AND LOW BLADE ASPECT RATIO. THE TURBINE SATISFIED THE EQUIVALENT DESIGN VALUE OF SPECIFIC WORK OUTPUT AT THE DESIGN CONDITION WITH AN EFFICIENCY OF 85.6%. IT IS CONCLUDED THAT THE PRESENT AIRFOIL SHAPES DESIGNED FOR AN AIR-COOLED...
Topics: AUSTENITIC STAINLESS STEELS, INTERGRANULAR CORROSION, SILICON, CHROMIUM ALLOYS, CORROSION...
This report presents the highlights of what has been ascertained about the interactions of liquid and vapor sodium, NaK potassium, lithium,, and cesium with solid materials of potential use in practical liquid-metal systems. Data for inclusion were selected by the authors on the basis of their practical utility to designers and research workers. There has been an accelerating interest in alkali metals as (1) coolants for fast-breeder nuclear reactors, (2) coolants in space power plants, (3)...
Topics: DTIC Archive, Stang, J H, BATTELLE MEMORIAL INST COLUMBUS OH DEFENSE METALS INFORMATION CENTER,...
The corrosion rates of several SNAP-21 materials measured in seawater at ambient room temperature and pressure (Hastelloy C, Hastelloy X, Titanium- 621, Berylco-165) have been compared to those measured in 200C seawater vapor (Hastelloy C, Hastelloy X), in seawater under a hydrostatic pressure of 7000 psi (Hastelloy C, Titanium-621, Berylco-165) (23C) and in seawater in an ionizing radiation field of 200,000 r/hr (Hastelloy C, Hastelloy X) (30C). Significant increases in corrosion rate were...
Topics: DTIC Archive, Kubose, Donald A, NAVAL RADIOLOGICAL DEFENSE LAB SAN FRANCISCO CA, *AUXILIARY POWER...
The addition, to a metallic matrix, of a suitably dispersed second phase is one of the most potent methods of increasing the strength of this matrix. In order to obtain a better understanding of the strengthening due to the presence of the second phase, extensive studies into dispersion strengthened alloys have been carried out over a number of years. Initially, these studies centered on the relationship of the observed mechanical properties to the size, shape and distribution of the second...
Topics: DTIC Archive, Grierson, Robert, ILIKON CORP NATICK MA, *TENSILE STRENGTH, *DISPERSION HARDENING,...
In this study, a systematic investigation of the fretting fatigue behavior of nickel alloy, IN-100 was carried out. The study includes both experimental work and the corresponding analysis of the contact conditions, and the latter is accomplished using the finite element method. Fretting fatigue tests were performed over a wide range of axial stresses to examine both low and high cycle fretting fatigue under constant contact load and the influence of different pad geometries was also explored....
Topics: DTIC Archive, Madhi, Elhoucine, AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH DEPT OF AERONAUTICS...
An analysis of the stresses in the axial stress-torsion test is presented by considering the gage section as a cylinder undergoing uniform axial deformation with superimposed torsion. Calculation of the stresses requires measurement of the radial deformation and penetration of the plastic region into the notch shoulders. The hydrostatic stress exhibits a peak within the wall of the gage section which increases with decreasing gage length. The fracture strain in room temperature tests increases...
Topics: DTIC Archive, Kuhn, H A, DREXEL INST OF TECH PHILADELPHIA PA DEPT OF METALLURGICAL ENGINEERING,...
The use of gas turbines in marine power plants depends in part on the development of superalloys which not only possess high temperature mechanical properties but also resist the corrosive effects of sea salt. A total of 137 experimental and commercial superalloys, both nickel and cobalt based, were exposed in burner rigs where controlled amounts of sea salt were added to the combustion products of sulfur-containing diesel fuel; test temperatures ranged from 1600 to 2125F; times ranges from 86...
Topics: DTIC Archive, Field, R, DAVID W TAYLOR NAVAL SHIP RESEARCH AND DEVELOPMENT CENTER ANNAPOLIS MD,...
This technical report reviews the available experimental data and information on the thermal linear expansion of nine AISI stainless steels and presents the recommended values from 10 K to near the melting point of the stainless steels. The nine selected stainless steels are AISI 303, 304, 304L, 316, 317, 321, 347, 410, and 430. The recommended values include the percent thermal linear expansion, the instantaneous coefficient, and the mean coefficient of thermal linear expansion. These values...
Topics: DTIC Archive, Desai, P D, THERMOPHYSICAL AND ELECTRONIC PROPERTIES INFORMATION ANALYSIS CENTER...
In an effort to reduce the unwanted effects of friction, ion implantation of bracket models was accomplished and tested against the four major orthodontic alloy groups, stainless steel (S.S.), cobalt-chromium (Co-Cr), nickel-titanium (NiTi), and beta-titanium. Stainless steel right-hand cylinders simulated orthodontic brackets. In addition to control samples, the polished faces of these cylinders were implanted with N+, Ti+/N+, N+/C+, N+/Cr+, Ti+, Ti+/C+, and C+. Frictional forces were...
Topics: DTIC Archive, Andrews, Stephen W, AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH, *FRICTION,...
This research, funded by the Department of Defense via the Research and Education Program for Historically Black Colleges and Universities and Minority-Serving Institutions (HBCU/MI), was conducted at the Applied Mechanics and Materials Research Laboratory, Howard University, Washington, DC from May 1, 2011 through October 31, 2014. The overall objective of the project is to develop and implement robust simulation-based strategies for notch root analysis and fatigue life prediction that account...
Topics: DTIC Archive, HOWARD UNIV WASHINGTON DC, *CRACKING(FRACTURING), *FATIGUE LIFE, *NOTCH TOUGHNESS,...
The effect of transition element binary solid solution additions upon the recry tallization temperature of nickel has been investigated. All additions raised the recrystallization temperature. Bot t e rate of change of recrystallization temperature with atomic percent solute and the limit of initial linearity are found to correlate with the free atom ground state outer electron configuration of the solute element.
Topics: DTIC Archive, ABRAHAMSON, ERNEST P , II, WATERTOWN ARSENAL LABS MA, *CRYSTALLIZATION, *NICKEL,...
This report deals with the physical metallurgy of Alloy 718. Since Alloy 718 was first introduced, it has broadened its areas of application. Primarily, it was intended for use at medium temperatures, 1300 F at most, its main applications being in lightweight welded frames and other assemblies in aircraft turbojet engines. Its good properties in the range of temperatures from -423 to 1300 F make it especially suitable for use in the LOX-LH4 rocket engines. In these applications, Alloy 718 is...
Topics: DTIC Archive, Wagner, H J, BATTELLE MEMORIAL INST COLUMBUS OH DEFENSE METALS INFORMATION CENTER,...
An experimental investigation is being conducted to evaluate the effect of very-low concentrations of sulfur in fuel on the durability of turbine-blade alloys when exposed under conditions simulating the environment in an aircraft-turbine engine operating in a marine environment. This has required development of a new turbine simulator, to increase productivity by simultaneous exposure of specimens and to improve precision by rotating specimens for uniform exposure in the high-velocity stream...
Topics: DTIC Archive, Quigg, H T, PHILLIPS PETROLEUM CO BARTLESVILLE OK RESEARCH AND DEVELOPMENT DEPT, *JET...
BACKGROUND: Corrosion protection is critical to long term ejection seat reliability and operation; Cadmium plating is used extensively in Propellant Actuated Devices (PAD) items. PRO's: Good corrosion protection; Thin enough for threads; good lubricity. CON's: Cadmium plater pool is drying up; EPA regulates cadmium in air; Cadmium toxic, carcinogenic. OBJECTIVES: Find a non-proprietary replacement, low toxicity, plating that provides corrosion protection which is equal to or greater than...
Topics: DTIC Archive, Archer, Jr, Harry L, NAVAL SEA SYSTEMS COMMAND DAHLGREN VA, *NICKEL ALLOYS, *PLATING,...
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Jul 11, 2010
07/10
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NON
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No Abstract Available
Topics: AIRCRAFT ENGINES, INCONEL (TRADEMARK), STRESS ANALYSIS, HEAT RESISTANT ALLOYS, NICKEL ALLOYS,...
Creep tests on Ni-based single crystal superalloy sheet specimens typically show greater creep strain rates and/or reduced strain or time to creep rupture for thinner specimens than predicted by current theories which predict a size independent creep strain rate and creep rupture strain. This size dependent creep response is termed the thickness debit effect. To investigate the mechanism of the thickness debit effect, isothermal, constant nominal stress creep tests were performed on uncoated...
Topics: DTIC Archive, UNIVERSITY OF NORTH TEXAS DENTON, *CREEP, *SINGLE CRYSTALS, *SUPERALLOYS, CREEP...
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1.6K
Jun 21, 2010
06/10
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NON
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Research and development studies for space program - instrumentation, communications, mechanical engineering, propulsion, systems analysis, and spacecraft advanced guidance
Topics: DIFFRACTOMETERS, HEAT RESISTANT ALLOYS, HIGH TEMPERATURE, X RAYS, COBALT ALLOYS, INDIUM ALLOYS,...
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May 21, 2011
05/11
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Prondzynski, Stephan
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In airplane construction generally one finds an almost exclusive use of wing tips that are practically square end but occasionally those with large rounded tips. For use as a cantilever wing, however, a wing with pointed tips may contain valuable aerodynamic advantages.
Topics: THEORIES - PLASTICITY, DISKS, ROTATING - STRENGTH, MATERIALS, STRESS-STRAIN, METALS - INCONEL X,...
The recent literature on embrittlement induced by solid or liquid metal environments is critically reviewed. Evidence in support of an enhanced shear model of embrittlement is provided for amorphous metals, while decohesion is shown to be a viable concept for crystalline metals. The usefulness of the concept of specificity of embrittlement is questioned on the basis of evidence for new embrittlement couples as the range of experimental conditions is varied. In particular, strain rate and...
Topics: DTIC Archive, Stoloff,Norman S, RENSSELAER POLYTECHNIC INST TROY NY DEPT OF MATERIALS ENGINEERING,...
The significant result is that the observed strengthening due to various types reinforcements (Al203 and TiB2) with same size is almost identical. The smaller size reinforcement 5 micrometers vs 150 micrometers produces greater strengthening. Also, the strengthening due to Al2O3 whiskers, which have long l/d (length to diameter) ratios of 10 to 100 is no greater than particulate Al203 and TiB2 of approximately the same size, which is a further indication that a load transfer mechanism is not...
Topics: DTIC Archive, Arsenault, R. J., MARYLAND UNIV COLLEGE PARK METALLURGICAL MATERIALS LAB, *METAL...
Certain characteristics of alloys of titanium and mixed (Nitinol) suggest that they may be superior materials from which to fashion Orthopaedic implants. Previous studies revealed that these alloys possess a critical transition temperature (TTR) over which the alloys undergo a highly unique electronic change and atomic repositioning associated with drastically altered mechanical properties such as elastic modulus and yield strength. Furthermore, When nitinol alloys are plastically deformed...
Topics: DTIC Archive, Hughes, James L, JOHNS HOPKINS UNIV BALTIMORE MD SCHOOLOF MEDICINE, *NICKEL ALLOYS,...
Shape memory alloys (SMAs) are a unique class of multifunctional materials that have the ability to recover large deformations or generate high stresses in response to thermal, mechanical and or electromagnetic stimuli. These abilities have made them a viable option for actuation systems in aerospace, medical, and automotive applications, amongst others. However, despite many advantages and the fact that SMA actuators have been developed and used for many years, so far they have only found...
Topics: NASA Technical Reports Server (NTRS), SHAPE MEMORY ALLOYS, THERMAL CYCLING TESTS, PHASE...
A three-phase program was completed to develop reliable, high temperature dynamic strain gage systems for application to turbine engine components operating to 1500 F. The strain gage element, intermediate leads and gage fabrication processes that evolved are used over the full temperature range: however, two different application techniques are required to achieve maximum fatigue strength to 1500 F. A composite-ceramic application design is recommended to 700 F. At higher temperatures, the...
Topics: DTIC Archive, Weise,R A, GENERAL ELECTRIC CO CINCINNATI OH AIRCRAFT ENGINE BUSINESS GROUP, *GAS...
A three-phase program was completed to develop reliable, high temperature dynamic strain gage systems for application to turbine engine components operating to 1500 F. The strain gage element, intermediate leads and gage fabrication processes that evolved are used over the full temperature range: however, two different application techniques are required to achieve maximum fatigue strength to 1500 F. A composite-ceramic application design is recommended to 700 F. At higher temperatures, the...
Topics: DTIC Archive, Weise,R A, GENERAL ELECTRIC CO CINCINNATI OH AIRCRAFT ENGINE BUSINESS GROUP, *GAS...
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Jul 11, 2010
07/10
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Donahue, T. M.; Hudson, R. D.; Rawlins, W. T.; Anderson, J.; Kaufman, F.; Mcelroy, M. B
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A technique devised to permit the measurement of atmospheric species concentrations is described. This technique involves the application of atomic absorption spectroscopy and the quantitative observation of resonance fluorescence in which atomic or molecular species scatter resonance radiation from a light source into a detector. A beam of atomic oxygen and atomic nitrogen resonance radiation, strong unabsorbable oxygen and nitrogen radiation, and visual radiation was sent from Apollo to...
Topics: BARRIER LAYERS, DIFFUSION, EUTECTICS, NICKEL ALLOYS, TUNGSTEN, GAS TURBINE ENGINES, HEAT RESISTANT...
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Jul 25, 2010
07/10
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Filgueirasdeazevedo, Joao Lui
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A numerical study of the aeroelastic stability of typical launch vehicle configurations in transonic flight is performed. Recent computational fluid dynamics techniques are used to simulate the transonic aerodynamic flow fields, as opposed to relying on experimental data for the unsteady aerodynamic pressures. The flow solver is coupled to an appropriate structural representation of the vehicle. The aerodynamic formulation is based on the thin layer approximation to the Reynolds-Averaged...
Topics: ALUMINUM ALLOYS, PHASE TRANSFORMATIONS, SINTERING, CHEMICAL COMPOSITION, CRYSTAL STRUCTURE, GIBBS...
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Jun 17, 2010
06/10
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Wood, J. A
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Widmanstatten structure in octahedrites from solid state transformations in slowly cooling nickel iron alloys - cooling rates and parent planets of iron meteorites
Topics: ANATASE, WIDMANSTATTEN STRUCTURE, IRON ALLOY, IRON METEORITE, NICKEL ALLOY, SOLID STATE PHYSICS,...
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Jul 12, 2010
07/10
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Bhat, B. N.; Davis, J. H
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Rolling contact fatigue (RCF) test specimens of heat treated 440C bearing steel were chromium ion plated in thicknesses from 0.1 to 8.0 micron and tested in RCF tester using 700 ksi maximum Hertzian stress. Heavy coatings, greater than about 5 micron in thickness, peeled off or spalled readily, whereas thin coatings, less than 3 micron thick, were tenacious and did not come off. Furthermore, significant improvement in RCF life was obtained with thin chromium ion plated test specimens. The...
Topics: ENGINE PARTS, NICKEL ALLOYS, THERMAL CYCLING TESTS, YTTRIUM ALLOYS, METAL COATINGS, PLASMA...
Description of the high temperature erosion facility at the University of Cincinnati is presented. A large portion of this investigation is devoted to the measurement and prediction of particle rebound characteristics. The abrasive particles were silica sand with average diameters of 165 microns impacting on the following materials: INCO 718, Ti 6-4, 2024 AL, RENE 150, Lead and Berillium. In addition, measurements of erosion rates were performed for materials used in jet engine blades....
Topics: DTIC Archive, Tabakoff,W, CINCINNATI UNIV OH DEPT OF AEROSPACE ENGINEERING AND APPLIED MECHANICS,...
This program included two major areas of research. In the processing area, a LAYERGLAZE (trade name) apparatus using a powder feed was developed and used to produce a 13.2 cm diameter by 3 cm thick cylindrical blank which was used as a preform for a scale model gas turbine disk. In addition to demonstrating that the process was capable of fabricating model size parts, mechanical testing and microstructural analysis of LAYERGLAZED material indicated that LAYERGLAZED parts exhibit good structural...
Topics: DTIC Archive, Breinan, E M, UNITED TECHNOLOGIES RESEARCH CENTER EAST HARTFORD CT, *LASER BEAMS,...
Foil gage superalloys are candidate materials for use in structural and heat shield panels for reentry and hypersonic vehicles. Unlike the coated refractory metals, little attention has been given to the potential environmental effects that may contribute to changes in mechanical properties of foil gage superalloys as a result of the low-pressure and slow-cyclic exposure of a typical hypersonic flight. The objective of this program was to investigate and evaluate operative degradation...
Topics: DTIC Archive, Malik, Raj K, SOLAR TURBINES INTERNATIONAL SAN DIEGO CA, *HEAT SHIELDS, *NICKEL...
The electroless deposition of nickel and cobalt from hypophosphite- based solutions has found numerous applications by virtue of characteristics unmatched by electrodeposition. For example, since deposition is produced by contact of the catalytic surface with the solution, exceptionally good deposit uniformity may be obtained. Also, the presence of phosphorus (from hypophosphite) in the deposits provides exceptional hardness (1) and corrosion resistance (2) to nickel and valuable magnetic...
Topics: DTIC Archive, Pearlstein, Fred, FRANKFORD ARSENAL PHILADELPHIA PA PITMAN-DUNN RESEARCH LABS,...
This work presents and discusses the available data and information on the thermal conductivity of ten selected binary alloy systems and contains the recommended reference values (or provisional or typical values) resulting from critical evaluation, analysis, and synthesis of the available data and information. The ten binary alloy systems are the systems of aluminum-copper, aluminum-magnesium, copper-gold, copper-nickel, and silver-palladium, copper-zinc, gold-palladium,...
Topics: DTIC Archive, Ho,C Y, THERMOPHYSICAL AND ELECTRONIC PROPERTIES INFORMATION ANALYSIS CENTER...
The hot corrosion resistance of nickel-chromium-aluminum alloy was examined by cyclically oxidizing sodium sulfate coated specimens in still air at 900, 1000 and 1100 C. The compositions tested were within the ternary region: Ni; Ni-50 at.% Cr; and Ni-50 at.% Al. At each temperature the corrosion data were statistically fitted to a third order regression equation as a function of chromium and aluminum contents. Corrosion isopleths were prepared from these equations. Compositional regions with...
Topics: NASA Technical Reports Server (NTRS), ALUMINUM ALLOYS, CHROMIUM ALLOYS, CORROSION RESISTANCE,...
Elevated temperature tensile and stress rupture properties were evaluated for forged TDNiCr (Ni-20Cr-2ThO2) and related to thermomechanical history and microstructure. Forging temperature and final annealed condition had pronounced influences on grain size which, in turn, was related to high temperature strength. Tensile strength improved by a factor of 8 as grain size changed from 1 to 150 microns. Stress-rupture strength was improved by a factor of 3 to 5 by a grain size increase from 10 to...
Topics: NASA Technical Reports Server (NTRS), CHROMIUM ALLOYS, FORGING, NICKEL ALLOYS, THERMODYNAMIC...
An improved material for use in a catalytic reactor which reduces nitrogen oxide from internal combustion engines is in the form of a zirconium-modified, precipitation-strengthened nickel-copper alloy. This material has a nominal composition of Ni-30 Cu-0.2 Zr and is characterized by improved high temperature mechanical properties.
Topics: NASA Technical Reports Server (NTRS), COPPER ALLOYS, NICKEL ALLOYS, REACTOR MATERIALS, ZIRCONIUM,...
Materials research and development was performed on diffusion bonding of titanium, machining of small-diameter holes, determination of the abrasive properties of materials in a simulated jet-engine environment, and determination of the properties of selected materials in a high-temperature corrosive and erosive environment.
Topics: DTIC Archive, Groh, Frederick G, PRATT AND WHITNEY AIRCRAFT GROUP EAST HARTFORD CT, *TURBOFAN...
This conference was organized to provide a forum for technically responsible representatives of government and industry to discuss the many facets of sulfidation corrosion and methods of reducing its effects. The major problem encountered in operating gas turbines in the marine environment is sulfidation, which limits engine life and restricts performance improvements. Sulfidation is also a significant problem with naval aircraft jet engines. Programs of common interest to surface ships and...
Topics: DTIC Archive, Miller, Charles L., NAVAL SHIP ENGINEERING CENTER WASHINGTON DC, *MARINE ATMOSPHERES,...
There has been a large impetus in recent years to extend fracture mechanics concepts to characterize high temperature crack growth. Several years ago McEvily and Wells(1) reviewed the application of these concepts to safe design in the creep range. Since then a large body of information on high temperature crack growth in a variety of structural alloys has been accumulated and there is a better understanding of the factors that affect crack growth and the limitations these factors impose on the...
Topics: DTIC Archive, Sadananda,K, NAVAL RESEARCH LAB WASHINGTON D C, *CRACK PROPAGATION, *NICKEL ALLOYS,...
The annealed Constantan foil materials currently used in bonded fatigue sensing devices have fatigue life and sensitivity limitations which place restraints upon practical application to long life service aircraft. These restraints have required the development of more compatible materials to meet present and future applications to fleet aircraft within the Air Force inventory. The effort was eventually directed toward the development of a vacuum deposited sensor. A selected composition of...
Topics: DTIC Archive, Horne, Robert S, LOCKHEED-GEORGIA CO MARIETTA, *FATIGUE(MECHANICS), *AIRFRAMES,...
An investigation of oxide dispersion strengthening (ODS) of oxidation resistant FeCrAlY alloys was conducted using argon atomized prealloyed powders and a modified SAP technique. The main objectives were to: improve surface stability; establish uniform powder pre-oxidation techniques; and improve the stress-rupture properties to the level exhibited by TD NiCr sheet. Increased chromium content proved very successful in eliminating 'breakaway' oxidation. Several powder pre-oxidation techniques...
Topics: DTIC Archive, Allen, R E, GENERAL ELECTRIC CO CINCINNATI OH MATERIAL AND PROCESS TECHNOLOGY LABS,...
A three-phase program was completed to develop reliable, high temperature dynamic strain gage systems for application to turbine engine components operating to 1500 F. The strain gage element, intermediate leads and gage fabrication processes that evolved are used over the full temperature range: however, two different application techniques are required to achieve maximum fatigue strength to 1500 F. A composite-ceramic application design is recommended to 700 F. At higher temperatures, the...
Topics: DTIC Archive, Weise,R A, GENERAL ELECTRIC CO CINCINNATI OH AIRCRAFT ENGINE BUSINESS GROUP, *GAS...
In order to understand the resistance of passive films formed during corrosion processes, an analytical technique using x-ray diffraction was developed to examine the structure of metal in closest proximity to the metal/liquid interface. The in-situ structure at the metal liquid interface was examined for pure nickel in sea water solution at room temperature and at two different potentiostatically controlled potentials (-800 mV and +450 mV versus Ni/NiO). The chemical changes at the metal...
Topics: DTIC Archive, Rao, Srinivasa, NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD SURVIVABILITY...
The understanding of the effect of material defects, i.e., inclusions and grain size variances, on tensile and fatigue behavior, specifically initiation, in wrought gamma titanium aluminides was improved. Orientation imaging microscopy (OIM) aided in determining microstructural situations favorable for initiation of fatigue cracks. Finite element models were refined to predict elastic and plastic behavior of fully lamellar microstructures under static loading. An effective ligament model that...
Topics: DTIC Archive, Ashbaugh, N E, DAYTON UNIV OH RESEARCH INST, *CERAMIC MATRIX COMPOSITES, *AEROSPACE...
This study was designed to quantify the cathodic efficiency of a graphite fiber reinforced epoxy laminated composite material by comparing the amount of zinc consumption from a sacrificial-anode cathodic protection system on the composite with the consumption due to a nickel-aluminum bronze in seawater. Specimens of the composite or of bronze were electrically coupled to anode zinc in seawater at flow velocities of 0 and 10 meters per second for up to 270 days. The composite did not cause a...
Topics: DTIC Archive, Hack, Harvey P., DAVID W TAYLOR NAVAL SHIP RESEARCH AND DEVELOPMENT CENTER ANNAPOLIS...
Corrosion products were developed on commercially available Cu-9.4 Ni-1.7 Fe alloy discs which rotated at 800 r.p.m. in 3.4 wt. % NaC1 solution with and without sulfide contamination for various lengths of time up to 10 days. The developed corrosion products were characterized with X-ray diffraction, SEM, and ESCA studies. Anodic and cathodic polarization curves were measured on the corrosion-product covered alloy surface as well as on the fresh surface to study the electrochemical behavior of...
Topics: DTIC Archive, Kato,Chiaki, PENNSYLVANIA STATE UNIV UNIVERSITY PARK APPLIED RESEARCH LAB,...
Few studies have been made on the stress/strain field or plastic zone size ahead of a crack tip in a high temperature environment under varying load frequencies and stress levels. Fewer studies have incorporated compressive loads or analyzed the effect of a negative R-ratio on the fatigue characteristics of the superalloy IN-100. This study involves extending existing analysis of the stress field and plastic zone ahead of a crack tip in a compact tension specimen, through a larger number of...
Topics: DTIC Archive, Wilson,R E, AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING,...
Nickel-Aluminum Bronze (NAB) is widely used for propulsion and seawater handling systems in naval platforms. It is selected because of its attractive combination of toughness and shock resistance but it has inherent susceptibility to selective phase corrosion and erosion-corrosion. In order to extend the life of NAB components, modern coating techniques are being considered in order to confer improved wear and corrosion resistance, as well as a method of providing cost effective refurbishment....
Topics: DTIC Archive, Barik, R C, SOUTHAMPTON UNIV (UNITED KINGDOM) SCHOOL OF ENGINEERING SCIENCES,...
