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in subjects: "Tungsten Base Alloys"  
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Calculated thickness of tungsten alloy required for specified attenuation of gamma radiation from sup 137 CS

Description: The traditional method of evaluating and calibrating health physics instruments is to use a calibrator that consists of a single high-activity gamma radiation source with different attenuators to select the radiation level desired for tesing. To have accurate radiation intensities inside the calibrator cavity, the attenuators must be designed from precise absorption calculations. This paper reports calculations made to determine the thickness of tungsten alloy metal required for specific attenu… more
Date: January 1, 1991
Creator: Chiles, M. M.; Allin, G. W. & Pace, J. V. III
Partner: UNT Libraries Government Documents Department
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Liquid-metal embrittlement of refractory metals by molten plutonium

Description: Embrittlement by molten plutonium of the refractory metals and alloys W-25 wt % Re, tantalum, molybdenum, and Ta-10 wt % W was studied. At 900/sup 0/C and a strain rate of 10/sup -4/ s/sup -1/, the materials tested may be ranked in order of decreasing susceptibility to liquid-plutonium embrittlement as follows: molybdenum, W-25 wt % Re, Ta-10 wt % W, and tantalum. These materials exhibited a wide range in susceptibility. Embrittlement was found to exhibit a high degree of temperature and strain… more
Date: July 1, 1980
Creator: Lesuer, D. R.; Bergin, J. B.; McInturff, S. A. & Kuhn, B. A.
Partner: UNT Libraries Government Documents Department
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Refractory alloy performance: unresolved issues and status summary

Description: Viewgraphs are included concerning the research work performed at ORNL on refractory alloys to be used in the SP-100 reactor design concepts. Mechanical properties and irradiation testing of the alloys are described.
Date: January 1, 1985
Creator: Harms, W.O.
Partner: UNT Libraries Government Documents Department
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Direct observation of densification and grain growth in a W--Ni alloy

Description: Densification and grain growth in a tungsten--nickel alloy containing 32 vol % of liquid at 1550/sup 0/C were studied by conventional methods aided by hot stage scanning electron microscopy and cinematography. This technique yields important additional qualitative information on the mechanisms. Two stages can be discerned. In stage 1, essentially complete pore elimination, rapid grain growth and adjustment of microstructural geometry take place. In the second stage, microstructure coarsening oc… more
Date: April 1, 1979
Creator: Riegger, H.; Pask, J.A. & Exner, H.E.
Partner: UNT Libraries Government Documents Department
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Heat resistant materials and their feasibility issues for a space nuclear transportation system

Description: A number of nuclear propulsion concepts based on solid-core nuclear propulsion are being evaluated for a nuclear propulsion transportation system to support the Space Exploration Initiative (SEI) involving the reestablishment of a manned lunar base and the subsequent exploration of Mars. These systems will require high-temperature materials to meet the operating conditions with appropriate reliability and safety built into these systems through the selection and testing of appropriate materials… more
Date: January 1, 1991
Creator: Olsen, C.S.
Partner: UNT Libraries Government Documents Department
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Sintering reactions, structure and properties of a cobalt free nonconventional hard material. [97. 5(95 W-3. 5 Ni-1. 5 Fe)-2. 5 B/sub 4/C; Mo-Ni-Fe-B/sub 4/C; W-Ni-Fe-B/sub 4/C]

Description: The compositional range of the metal-boron-carbon family of hard metals was extended to yield the wide density range of approx. 7.8 to 17.1 Mg/m/sup 3/ with only a small spread in hardness values. The abrasion resistance and fracture toughness of several compositions were in the range of some commercial grades of wear resistant tungsten carbide-cobalt hard metals. Hot microhardness of one composition was 10 to 20% higher than any premium grade conventional tungsten carbide-cobalt. A 95.0 wt % W… more
Date: January 1, 1985
Creator: Sheinberg, H.
Partner: UNT Libraries Government Documents Department
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Effects of rolling on the ductility of 80% tungsten heavy alloy

Description: Relations between transverse tensile ductility and rolling and annealing schedules were investigated for solid-state sintered and annealed 80%W8%Ni-2%Fe heavy alloy rolled at 900C or 1150C with varying reductions between anneals at either 1150C or 1400C. Final anneals and a solution heat treatment were employed prior to tensile testing. Metallographic and fractographic analyses were performed to determine relations between microstructure and physical properties. Multiple 1400C intermediate anne… more
Date: November 1, 1992
Creator: Lavender, C. A. & Gurwell, W. E.
Partner: UNT Libraries Government Documents Department
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Atom-probe field-ion microscope for the study of the interaction of impurity atoms or alloying elements with defects

Description: A time-of-flight (TOF) atom-probe field-ion microscope (FIM) designed for the study of defects is described. This atom probe features: (1) a variable magnification internal-image-intensification system; (2) a liquid-helium goniometer stage; (3) a low-energy (less than or equal 3 keV) gas-ion gun for in-situ irradiations; (4) an ultra-high vacuum (approximately 3.10/sup -10/ torr) chamber; (5) a high vacuum (approximately 10/sup -6/ torr) specimen-exchange device; (6) a Chevron ion detector; and… more
Date: October 1, 1976
Creator: Wagner, A.; Hall, T. M. & Seidman, D. N.
Partner: UNT Libraries Government Documents Department
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Bend ductility of tungsten heavy alloys

Description: A bend ductility test is used to indicate the formability of tungsten heavy alloys sheet. The primary test bends a notchless Charpy impact specimen to a bend angle of approximately 100C. This can be augmented by a bend-completion test. Finite element modeling as well as strain-gaged bend specimens elucidate the strain distribution in the specimen as a function of material thickness and bend angle. The bend ductilities of 70%W, 807.W and 90%W alloys are characterized. As expected, decreasing thi… more
Date: November 1, 1992
Creator: Gurwell, W. E.; Garnich, M. R.; Dudder, G. B. & Lavender, C. A.
Partner: UNT Libraries Government Documents Department
open access

Proceedings of the Tungsten Workshop for Hard Target Weapons Program

Description: The purpose of this meeting was to review and exchange information and provide technical input for improving technologies relevant to the Hard Target Weapons Program. This workshop was attended by representatives from 17 organizations, including 4 Department of Defense (DoD) agencies, 8 industrial companies, and 5 laboratories within DOE. Hard targets are defined as reinforced underground structures that house enemy forces, weapon systems, and support equipment. DOE-ORO and Martin Marietta Ener… more
Date: June 1, 1995
Creator: Mackiewicz-Ludtka, G.; Hayden, H.W. & Davis, R.M.
Partner: UNT Libraries Government Documents Department
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Chemical vapor deposition of refractory ternary nitrides for advanced diffusion barriers

Description: Refractory ternary nitride films for diffusion barriers in microelectronics have been grown using chemical vapor deposition. Thin films of titanium-silicon-nitride, tungsten-boron-nitride, and tungsten-silicon-nitride of various compositions have been deposited on 150 mm Si wafers. The microstructure of the films are either fully amorphous for the tungsten based films, or nauocrystalline TiN in an amorphous matrix for titanium-silicon-nitride. All films exhibit step coverages suitable for use i… more
Date: September 22, 1998
Creator: Custer, Jonathan S.; Fleming, James G.; Roherty-Osmun, Elizabeth & Smith, Paul Martin
Partner: UNT Libraries Government Documents Department
open access

Effects of rolling on the ductility of 80% tungsten heavy alloy

Description: Relations between transverse tensile ductility and rolling and annealing schedules were investigated for solid-state sintered and annealed 80%W8%Ni-2%Fe heavy alloy rolled at 900C or 1150C with varying reductions between anneals at either 1150C or 1400C. Final anneals and a solution heat treatment were employed prior to tensile testing. Metallographic and fractographic analyses were performed to determine relations between microstructure and physical properties. Multiple 1400C intermediate anne… more
Date: November 1, 1992
Creator: Lavender, C.A. & Gurwell, W.E.
Partner: UNT Libraries Government Documents Department
open access

LANSCE target calculations

Description: The LANSCE target operates at a beam current of 30 microamps. We present here the results of the finite-element calculations for the temperatures and stresses in the present target operated at 100 microamps. The calculations were run using the ABAQUS finite-element code. All finite-element codes require as input both the boundary conditions for the material being heated, and such material properties as the thermal conductivity, specific heat, and the elastic modulus. For the LANSCE target, the … more
Date: January 1, 1989
Creator: Grisham, D. L. & Brown, R. D.
Partner: UNT Libraries Government Documents Department
open access

Bend Ductility of Tungsten Heavy Alloys

Description: A bend ductility test is used to indicate the formability of tungsten heavy alloys sheet. The primary test bends a notchless Charpy impact specimen to a bend angle of approximately 100C. This can be augmented by a bend-completion test. Finite element modeling as well as strain-gaged bend specimens elucidate the strain distribution in the specimen as a function of material thickness and bend angle. The bend ductilities of 70%W, 807.W and 90%W alloys are characterized. As expected, decreasing thi… more
Date: November 1992
Creator: Gurwell, W. E.; Garnich, M. R.; Dudder, G. B. & Lavender, C. A.
Partner: UNT Libraries Government Documents Department
open access

Refractory metal alloys and composites for space nuclear power systems

Description: Space power requirements for future NASA and other United States missions will range from a few kilowatts to megawatts of electricity. Maximum efficiency is a key goal of any power system in order to minimize weight and size so that the space shuttle may be used a minimum number of times to put the power supply into orbit. Nuclear power has been identified as the primary power source to meet these high levels of electrical demand. One method to achieve maximum efficiency is to operate the power… more
Date: January 1, 1988
Creator: Titran, Robert H.; Stephens, Joseph R. & Petrasek, Donald W.
Partner: UNT Libraries Government Documents Department
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Predictions of radioactive tungsten release for hypothetical ITER (International Thermonuclear Experimental Reactor) accidents

Description: Postulated long-term loss of coolant accidents (LOCA) for the International Thermonuclear Experimental Reactor (ITER) may involve the ingress of air or steam into the plasma chamber. Reactions of these gases with the hot plasma facing components will cause oxidation, transport, and release of activated species. To predict radioactivity releases, we measured volatility rates from a tungsten alloy. Tests were performed in air or steam between 600 and 1200{degree}C for 1 to 20 h. We used these vol… more
Date: January 1, 1990
Creator: Smolik, G. R.; Piet, S. J. & Neilson, R. M., Jr.
Partner: UNT Libraries Government Documents Department
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Volatility from copper and tungsten alloys for fusion reactor applications

Description: Accident scenarios for fusion power plants present the potential for release and transport of activated constituents volatilized from first wall and structural materials. The extent of possible mobilization and transport of these activated species, many of which are oxidation driven'', is being addressed by the Fusion Safety Program at the Idaho National Engineering Laboratory (INEL). This report presents experimental measurements of volatilization from a copper alloy in air and steam and from … more
Date: January 1, 1989
Creator: Smolik, G. R.; Neilson, R. M., Jr. & Piet, S. J.
Partner: UNT Libraries Government Documents Department
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A photon shield capsule design for an {sup 241}Am/Be ({alpha},n) source using high density tungsten alloy

Description: A photon shield capsule made of high density tungsten alloy was designed for a 400 GBq {sup 241}Am/Be ({alpha},n) NIST-traceable source using Monte Carlo calculations. The {sup 241}Am/Be ({alpha},n) source replaces a {sup 239}Pu/Be ({alpha},n) source used in the Los Alamos Neutron Well for dose rate calibrations of portable and fixed neutron rem meters. Potential operator exposure due to {sup 241}Am photon emission (E{sub {gamma}} = 59.5 keV, Y{sub {gamma}} = 0.357 {gamma} d{sup -1}) is a major… more
Date: January 1, 1997
Creator: Clement, R. S.; Hsu, H. H.; Olsher, R. S. & Aikin, D. J.
Partner: UNT Libraries Government Documents Department
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Alternative processing methods for tungsten-base composite materials

Description: Tungsten composite materials contain large amounts of tungsten distributed in a continuous matrix phase. Current commercial materials include the tungsten-nickel-iron with cobalt replacing some or all of the iron, and also tungsten-copper materials. Typically, these are fabricated by liquid-phase sintering of blended powders. Liquid-phase sintering offers the advantages of low processing costs, established technology, and generally attractive mechanical properties. However, liquid-phase sinteri… more
Date: December 31, 1995
Creator: Ohriner, E. K. & Sikka, V. K.
Partner: UNT Libraries Government Documents Department
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0.5 μm E/D AlGaAs/GaAs heterostructure field effect transistor technology with DFET threshold adjust implant

Description: A doped-channel heterostructure field effect transistor (H-FET) technology has been developed with self-aligned refractory gate processing and using both enhancement- and depletion-mode transistors. D-HFET devices are obtained with a threshold voltage adjust implant into material designed for E-HFET operation. Both E- and D-HFETs utilize W/WSi bilayer gates, sidewall spacers, and rapid thermal annealing for controlling short channel effects. The 0.5 {mu}m E- HFETs (D-HFETs) have been demonstrat… more
Date: April 1997
Creator: Baca, A. G.; Sherwin, M. E.; Zolper, J. C.; Shul, R. J.; Briggs, R. D.; Heise, J. A. et al.
Partner: UNT Libraries Government Documents Department
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Comparison of calculated and experimental results of fragmenting cylinder experiments

Description: The Grady-Kipp fragmentation model provides a physically based method for determining the fracture and breakup of materials under high loading rates. Recently, this model has been implemented into the CTH Shock Physics Code and has been used to simulate several published experiments. Materials studied in this paper are AerMet 100 steel and a 90% tungsten alloy. The experimental geometry consists of a right circular cylinder filled with an explosive main charge that is initiated at its center. T… more
Date: June 2, 2000
Creator: Wilson, L. T.; Reedal, D. R.; Kipp, Marlin E.; Martinez, Reina R. & Grady, D. E.
Partner: UNT Libraries Government Documents Department
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Design analysis of a composite L5-80 slit for x-ray beamlines at the Advanced Photon Source

Description: White-beam slits are precision high-heat-load devices used on beamlines of the Advanced Photon Source (APS) to trim and shape the incoming x-rays beam before the beam is transmitted to other optical components. At the APS, the insertion devices that generate the x-ray are very powerful. For example, the heat flux associated with an x- ray beam generated by Undulator A will be on the order of 207 W/mm{sup 2} at the L5-80 slit location (about 27.5 m away from the insertion device) at normal incid… more
Date: December 31, 1996
Creator: Nian, H. L. T.; Kuzay, T. M. & Shu, D.
Partner: UNT Libraries Government Documents Department
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Dynamic strength and strain rate effects on fracture behavior of tungsten and tungsten alloys

Description: An investigation of the stress-strain response as a function of strain rate, spall strength, and dynamic fracture behavior of pure W, W-26Re, W-Ni-Fe and W-Ni-Fe-Co has been performed. Spall strength measurements, obtained in symmetric-impact tests, showed an increase in spall strength from 0.4 GPa for pure tungsten to 3.8 GPa for 90W- 7Ni-3Fe. Concurrent with increase in spall strength was a change in fracture mode from cleavage (for pure W) to a mixture of transgranular and intergranular frac… more
Date: January 1, 1991
Creator: Zurek, A. K. & Gray, G. T., III
Partner: UNT Libraries Government Documents Department
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