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The Vanadium-Uranium Constitutional Diagram

Description: Abstract: "Vanadium-uranium equilibrium studies were made on alloys prepared from high-purity vanadium and good biscuit uranium. No intermetallic phases occur in the system. Additions of vanadium lover the uranium melting point and transformations producing a eutectic at 1240 +/- 5 C and eutectoid reactions at 727 +/- 5 and 652 +/- 5 C. The maximum solubility of uranium in vanadium is about 4 atomic per cent (15 weight per cent)."
Date: December 15, 1951
Creator: Saller, Henry A. & Rough, Frank A.
Partner: UNT Libraries Government Documents Department

Hydrogen Release from Irradiated Vanadium Alloy V-4Cr-4Ti

Description: The present work is an attempt to obtain data concerning the influence of neutron and ? irradiation upon hydrogen retention in V-4Cr-4Ti vanadium alloy. The experiments on in-pile loading of vanadium alloy specimens at the neutron flux density 1014 n/cm2s, hydrogen pressure of 80 Pa, and temperatures of 563, 613, and 773 K were carried out using the IVG.1M reactor of the Kazakhstan National Nuclear Center. A preliminary set of loading/degassing experiments with non-irradiated material has been carried out to obtain data on hydrogen interaction with vanadium alloy. The, data presented in this work are related both to non-irradiated and irradiated samples.
Date: September 1, 1999
Creator: Klepikov, A. Kh.; Romanenko, O. G.; Chikhray, E. V.; Tazhibaeva, I. L.; Shestakov, V. P. & Longhurst, Glen Reed
Partner: UNT Libraries Government Documents Department

ALCHEMI of niobium dichrome/vanadium C15 Laves phase

Description: 33Nb42Cr25V was prepared by arc melting and annealing at 1400 C for 120 hr. Energy-dispersive x-ray spectra were collected over a range of {l_brace}400{l_brace} excitations between symmetry and beyond {l_brace}12 0 0{l_brace}. Results show that at least qualitatively V substitutes for Cr. Therefore, electronic effects must be more important than size effects in this case.
Date: May 1, 1996
Creator: Kotula, P.G.; Chu, Fuming; Mitchell, T.E.; Anderson, I.M. & Bentley, J.
Partner: UNT Libraries Government Documents Department

Engineering design of a radiative divertor for DIII-D

Description: A new divertor configuration is being developed for the DIII-D tokamak. This divertor will operate in the radiative mode. Experiments and modeling form the basis for the new design. The Radiative Divertor reduces the heat flux on the divertor plates by dispersing the power with radiation in the divertor region. In addition, the Radiative Divertor structure will allow density control in plasma shapes required for advanced tokamak operation. The divertor structure allows for operation in either double-null or single-null plasma configurations. Four independently controlled divertor cryopumps will enable pumping at either the inboard (upper and lower) or the outboard (upper and lower) divertor plates. An upgrade to the DIII-D cryogenic system is part of this project. The increased capabilities of the cryogenic system will allow delivery of liquid helium and nitrogen to the three new cryopumps. The Radiative Divertor design is very flexible, and will allow physics studies of the effects of slot width and length. Radiative Divertor diagnostics are being designed in parallel to provide comprehensive measurements for diagnosing the divertor. The Radiative divertor installation is scheduled for late 1996. Engineering experience gained in the DIII-D Advanced Divertor program form a foundation for the design work on the Radiative Divertor.
Date: October 1, 1995
Creator: Smith, J.P.; Baxi, C.B. & Bozek, A.S.
Partner: UNT Libraries Government Documents Department

Analysis of the e-beam evaporation of titanium and Ti-6Al-4V

Description: An experimental and finite element analysis was performed for the electron-beam evaporation of Ti and Ti-6Al-4V from a bottom-feed system. The bulk evaporation rate was measured by feed consumption, and the pool elevation was held constant by adjusting the feed rate in a closed-loop control system. The instantaneous titanium and aluminum evaporation rates were determined by laser absorption in the vapor plume. Water temperature rises in cooling water circuits provided heat flows, and post-run cross sections revealed the location of the solidification zone. The MELT finite element code was applied to model the steady-state two-dimensional fluid flow and energy transport in the rod. There was good agreement between model and measured values of the heat flows and solidification boundaries for Ti. Measured bulk evaporation rates were similar for Ti and Ti-6-4 with greater variation observed for the Ti values. The model evaporation rates were higher than the measured values, but a similar linear dependence on e-beam power was observed in all cases. In a Ti-6-4 evaporation experiment with steady process conditions, laser absorption measurements showed much larger fluctuations in the evaporation rate for Al than Ti.
Date: February 11, 1998
Creator: Westerberg, K.W.; Merier, T.C.; McClelland, M.A.; Braun, D.G.; Berzins, L.V.; Anklam, T.M. et al.
Partner: UNT Libraries Government Documents Department

Integrated approach to advanced machining

Description: The residual stress state induced by machining in a Ti alloy as function of cutting tool sharpness and depth of cut was predicted and measured. Residual stresses were greater for the dull tool than for the sharp tool. XRD was used to measure the residual stress state of the material; these measurements revealed that the hoop stress increased with depth of cut; however the radial stress decreased with depth of cut. An elastic-plastic model provided a possible explanation for this behavior in that, for small depths of cut, the tool makes multiple passes through the damage subsurface layer. This causes both residual stress components to increase, but the radial stress increases by a much greater amount than the hoop stress.
Date: August 1, 1997
Creator: LeSar, R.A.; Bourke, M.A.M.; Rangaswamy, P.; Day, R.D. & Hatch, D.J.
Partner: UNT Libraries Government Documents Department

C15 intermetallic compounds HfV{sub 2}+Nb

Description: Phase fields and equilibria in the Hf-V-Nb system were determined using a combination-of SEM, EDS and x-ray diffraction. The structural stability of the C15 HfV{sub 2+}Nb was studied by x-ray diffraction and specific heat measurements. The elastic constants of C15 HfV{sub 2+}Nb were measured by the resonant ultrasound spectroscopy technique. First-principle quantum mechanical calculations based on the local-density-functional theory have been employed to study the total energy and electronic structure of C15 HfV{sub 2}, which can be used to understand the physical and metallurgical properties of the C15 intermetallics HfV{sub 2+}Nb.
Date: December 31, 1994
Creator: Chu, F.; Chen, S.P.; Mitchell, T.E.; Pope, D.P. & Liu, C.T.
Partner: UNT Libraries Government Documents Department

Numerical simulation of industrial superplastic forming

Description: Superplastic forming is a metal forming process that allows a variety of components with very complex geometries to be produced at one tenth the cost of conventional machining. The industrial superplastic forming process can be optimized with the application of the finite element method to predict the optimal applied pressure history and the final part thickness distribution. This paper discusses the application the nonlinear implicit, three dimensional finite element code, NIKE3D to the problem of numerically simulating and optimizing the superplastic forming of Ti-6AI-4V components.
Date: March 1, 1995
Creator: Haberman, K.S.; Bennett, J.G.; Miller, E.L.; Piltch, M.S.; Leyer, L.K. & Leodolter, W.
Partner: UNT Libraries Government Documents Department

Performance of V-4Cr-4Ti material exposed to the DIII-D Tokamak environment.

Description: A series of tests is being conducted in the DIII-D tokamak to determine the effects of environmental exposure on a V-4Cr-4Ti vanadium alloy. These tests are part of the effort to build and install a water-cooled vanadium alloy structure in the DIII-D radiative diverter upgrade. Data from the test series indicate that the performance of the V-4Cr4Ti alloy would not be significantly affected by environmental exposure. Interstitial absorption by the material appears to be limited to the surface, and neither the tensile nor the impact properties of the material appear to be affected by the exposure.
Date: May 18, 1998
Creator: Tsai, H.; Smith, D. L.; Chung, H. M.; Johnson, W. R.; Smith, J. P. & Wampler, W. R.
Partner: UNT Libraries Government Documents Department

Alloys of Uranium with Zirconium, Chromium, Columbium, Vanadium, and Molybdenum

Description: Abstract: Information on five uranium binary alloy systems has been surveyed. These systems are the alloys of uranium with zirconium, chromium, columbium, vanadium, and molybdenum. The equilibrium diagrams are discussed, and where available, data have been included on diffusion studies, cladding experiments, and mechanical properties.
Date: June 19, 1952
Creator: Saller, Henry A. & Rough, Frank A.
Partner: UNT Libraries Government Documents Department

Transformations in uranium-base alloys : summary report, December 14, 1955 - March 31, 1957

Description: From abstract: "Transformation kinetics of binary U -Nb and ternary U-Nb-base alloys were investigated. Additions included zirconium, chromium, titanium, silicon, nickel, nnthenium, and vanadium. Encapsulated samples were given a homogenizstion anneal at 1000 or 1100/sup o/C, water-quenched from 906/sup o/C to retain the phase, and reheated to temperatures between 360 and 600/sup o/C. The metastability of the phase was examined by metallographic, hardness, resistometric, dilatometric and x-ray-diffraction techniques. The U -Nb system is characterized by a monotectoid decomposition of the high temperature allotrope at about 645/sup o/C to form alpha and ₂, a niobium-rich cubic structure. Decomposition in U-Nb and in most U-Nb-X alloys occurred by a continuous precipithtion of alpha from the body-centered cubic phase with a resultant enrichment in niobium of until the equilibrium ₂ composition was reached. In the U-Nb-Ti and U-Nb-V systems, alpha and /sub 2/ were coprecipitated. Annealing at 550 and 600/sup o/C produced decomposition products which, in most materials, originated at the grain boundaries; a fine precipitate which initiated throughout the matrix was observed at lower annealing temperatures. Increasing the niobium content resulted in greatly increased stability. The following elements added to a U-Nb base were found to retard transformation of the phase: zirconium, chromium, ruthenium, and vanadium. Additions of titanium, silicon, and nickel produced alloys which were less stable than the U-Nb base to which they were added. Cold-working a U-7 wt. % Nb-2 wt. % Zr composition caused a more rapid transformation upon annealing at 360 and 450/ sup o/C, and the resulting microstructures were different. Continuous cooling transformation studies were conducted on U-10 wt. % Nb materials, solution annealed at 700 and 950°C, and cooled at various linear rates to temperatures between 300 and 600/sup o/C. Cooling rates between 8.5 and 14.5/sup o/C per minute were required to prevent transformation of ...
Date: 1957
Creator: Parry, Sidney J. S.; Holtz, F. C. & Van Thyne, R. J.
Partner: UNT Libraries Government Documents Department

The effects of in-situ processing methods on the microstructure and fracture toughness of V-V{sub 3}Si composites

Description: This paper describes ductile-phase roughening in V-V{sub 3}Si in-situ composites produced by conventional arc melting (AM), cold-crucible induction melting (IM), and cold-crucible directional solidification (DS). Notched three-point bending tests were performed to determine the effects of synthesis method on the room temperature fracture toughness of eutectic compositions, which contain nearly equal volume fractions of V{sub 3}Si and the V(Si) solid solution phase. Fracture toughness values ranged from 10 MPa{radical}m for the AM eutectic to over 20 MPa{radical}4m for the IM and DS eutectic alloys. SEM fractography, surface profiling, and chemical analyses were performed to correlate the toughness values with the microstructures and interstitial concentrations produced by the three synthesis methods.
Date: November 19, 1993
Creator: Strum, M. J.; Henshall, G. A.; Bewlay, B. P.; Sutliff, J. A. & Jackson, M. R.
Partner: UNT Libraries Government Documents Department

Excimer laser processing of tool steel: Tribological effects of multiple pulse processing and titanium alloying

Description: Excimer lasers were used to modify the surface of AISI type A-7 tool steel, a high C, high V, high Cr material used in many cutting applications. Multiple pulses of laser radiation at 248 nm were used to alter the composition of the surface alloy. Hardness and modulus were not significantly affected by the treatment, but friction in dry sliding against an alumina pin was reduced. The reduction was small but persistent for multiply melted and resolidified surfaces. These surfaces showed a marked increase in the surface Cr concentration. Greater reductions in friction were obtained from a Ti rich surface layer formed by laser mixing an evaporated Ti layer into the material. The friction coefficient of the Ti alloyed surface deteriorated after approximately 1000 cycles, indicating wear=through of the modified surface. The observed properties will be discussed in terms of the excimer laser modification process and the microstructure and composition of the resulting surfaces.
Date: December 1, 1995
Creator: Jervis, T.R.; Nastasi, M.; Griffin, A.J. Jr.; Zocco, T.G.; Taylor, T.N. & Foltyn, S.R.
Partner: UNT Libraries Government Documents Department

Analysis of the interphase of a polyamide bonded to chromic acid anodized Ti-6AL-4V

Description: Structural adhesive joints, when tested as made, typically fail cohesively through the centerline of the adhesive. However, in any study of adhesive joint durability, failure near the adhesive/substrate interface becomes an important consideration. In the current study, an interfacially debonding adhesive test, the notched coating adhesion (NCA) test, was applied to LaRC(trademark) PETI-5 adhesive bonded to chronic acid anodized (CAA) Ti-6Al-4V. Post-failure analysis of the interphase region included X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), field emission scanning electron microscopy (FE-SEM), and atomic force microscopy (AFM). Mechanical interlocking between an adhesive and a substrate occurs when the liquid adhesive flows into interstices of the substrate, solidifies, and becomes locked in place. Mechanical interlocking is believed to significantly contribute to the adhesion of substrates that exhibit microroughness, such as metal surfaces treated with chromic acid anodization or sodium hydroxide anodization. Filbey and Wightman found that an epoxy penetrated the pores of CAA Ti-6Al-4V, one of the limited number of pore penetration studies that have been reported. In the current study, the penetration of PETI-5 into the pores of CAA Ti-6Al-4V is investigated through analysis of adhesive/substrate failure surfaces.
Date: January 6, 2000
Creator: Guinta, R.K. & Kander, R.G.
Partner: UNT Libraries Government Documents Department

Progress in vanadium alloy development for fusion applications

Description: Vanadium alloys have been identified as a leading candidate low- activation structural mateiral for fusion first-wall blanket applications. Candidate vanadium alloys exhibit favorable safety and environmental characteristics, good fabricability, high temperature and heat load capability, good compatibility with liquid metals and resistance to irradiation damage. The focus of the vanadium alloy development program has been on the vanadium-chromium-titanium (0-15% Cr, 1-20% Ti) alloy system. Investigations include effects of minor alloy elements such as Si, Al, and Y and substitution of iron fro chromium in the ternary alloy. A V-4Cr-4Ti alloy is currently regarded as the reference alloy. Significant progress has been made in the development of vanadium alloys for fusion applications, Two production-scale heats (500 kg and 1200 kg) of the V-4Cr-4Ti alloys have been produced with controlled levels of impurities. The baseline properties of the 500 kg heat are similar to those of the previous laboratory-scale heats. Additional data have been obtained on baseline tensile and fracture properties. Results obtained on several heats with minor variations in composition indicate high uniform and total elongation of these alloys at temperatures of 400-600{degrees}C. The properties are not significantly different when modest amounts of helium are generated during neutron irradiation by the Dynamic Helium Charging Experiment methods. However, recent results have indicated that these alloys are susceptible to irradiation embrittlement at lower temperatures. Additional irradiation experiments are in progress to investigate these effects at temperatures of 200-400{degrees}C. This paper presents and update on the experimental results on candidate low activation vanadium alloys.
Date: April 1, 1997
Creator: Smith, D.L.; Chung, H.M.; Matsui, H. & Rowcliffe, A.F.
Partner: UNT Libraries Government Documents Department

Tensile and impact properties of V-4Cr-4Ti alloy heats 832665 and 832864.

Description: Two large heats of V-4Cr-4Ti alloy were produced in the United States in the past few years. The first, 832665, was a 500 kg heat procured by the U.S. Department of Energy for basic fusion structural materials research. The second, 832864, was a 1300 kg heat procured by General Atomics for the DIII-D radiative divertor upgrade. Both heats were produced by Oremet-Wah Chang (previously Teledyne Wah Chang of Albany). Tensile properties up to 800 C and Charpy V-notch impact properties down to liquid nitrogen temperature were measured for both heats. The product forms tested for both heats were rolled sheets annealed at 1000 C for 1 h in vacuum. Testing results show the behavior of the two heats to be similar and the reduction of strengths with temperature to be insignificant up to at least 750 C. Ductility of both materials is good in the test temperature range. Impact properties for both heats are excellent--no brittle failures at temperatures above -150 C. Compared to the data for previous smaller laboratory heats of 15-50 kg, the results show that scale-up of vanadium alloy ingot production to sizes useful for reactor blanket design can be successfully achieved as long as reasonable process control is implemented.
Date: November 8, 1999
Creator: Bray, T. S.; Tsai, H.; Nowicki, L. J.; Billone, M. C.; Smith, D. L.; Johnson, W. R. et al.
Partner: UNT Libraries Government Documents Department

Overview of design activities for Li/V blankets

Description: Recent fusion power plant design studies in the US have been conducted within the ARIES project. The most recent design of Li/V blankets was conducted as part of the ARIES-RS design. The ARIES-RS fusion power plant design study is based on reversed-shear (RS) physics with a Li/V (lithium breeder and vanadium structure) blanket. The reversed-shear discharge has been documented in many large tokamak experiments. The plasma in the RS mode has a high beta, low current, and low current drive requirement. Therefore, it is an attractive physics regime for a fusion power plant. The blanket system based on a Li/V has high temperature operating capability, good tritium breeding, excellent high heat flux removal capability, long structural life time, low activation, low after heat and good safety characteristics. For these reasons, the ARIES-RS reactor study selected Li/V as the reference blanket. The combination of attractive physics and attractive blanket engineering is expected to result in a superior power plant design.
Date: December 31, 1997
Creator: Sze, D.K. & Mattas, R.F.
Partner: UNT Libraries Government Documents Department

Modeling of shear localization in materials

Description: The deformation response of a Ti alloy, Ti-6Al-4V, has been studied during shear localization. The study has involved well-controlled laboratory tests involving a double-notch shear sample. The results have been used to provide a comparison between experiment and the predicted response using DYNA2D and two material models (the Johnson-Cook model and an isotropic elastic-plastic-hydrodynamic model). The work will serve as the basis for the development of a new material model which represents the different deformation mechanisms active during shear localization.
Date: February 11, 1998
Creator: Lesuer, D.; LeBlanc, M.; Riddle, B. & Jorgensen, B.
Partner: UNT Libraries Government Documents Department

Structural design criteria for high heat flux components.

Description: The high temperature design rules of the ITER Structural Design Criteria (ISDC), are applied to first wall designs with high heat flux. The maximum coolant pressure and surface heat flux capabilities are shown to be determined not only by the mechanical properties of the first wall material but also by the details of the blanket design. In a high power density self-cooled lithium blanket, the maximum primary stress in the first wall is controlled by many of the geometrical parameters of the blanket, such as, first wall span, first wall curvature, first wall thickness, side wall thickness, and second wall thickness. The creep ratcheting lifetime of the first wall is also shown to be controlled by many of the same geometrical parameters as well as the coolant temperature. According to most high temperature design codes, the time-dependent primary membrane stress allowable are based on the average temperature (ignoring thermal stress). Such a procedure may sometimes be unconservative, particularly for embrittled first walls with large temperature gradients. The effect of secondary (thermal) stresses on the accumulation of creep deformation is illustrated with a vanadium alloy flat plate first wall design.
Date: July 14, 1999
Creator: Majumdar, S.
Partner: UNT Libraries Government Documents Department

Irradiation creep of vanadium-base alloys.

Description: A study of irradiation creep in vanadium-base alloys is underway with experiments in the Advanced Test Reactor (ATR) and the High Flux Isotope Reactor (HFIR) in the US. Test specimens are thin-wall sealed tubes with internal pressure loading. The results from the initial ATR irradiation at low temperature (200-300 C) to a neutron damage level of 4.7 dpa show creep rates ranging from {approx}0 to 1.2 x 10{sup {minus}5}/dpa/MPa for a 500-kg heat of V-4Cr-4Ti alloy. These rates were generally lower than reported from a previous experiment in BR-10. Because both the attained neutron damage levels and the creep strains were low in the present study, however, these creep rates should be regarded as only preliminary. Substantially more testing is required before a data base on irradiation creep of vanadium alloys can be developed and used with confidence.
Date: May 18, 1998
Creator: Tsai, H.; Matsui, H.; Billone, M. C.; Strain, R. V. & Smith, D. L.
Partner: UNT Libraries Government Documents Department