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in creator/contributor: "Braski, D. N."

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Anomalous behavior in the kinetics of phase transformation in CsCl--KCl system

No Description Available.

Date: May 1, 1973

Creator: Lin, K. H. & Braski, D. N.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Production of Ir--0.3% W disks and foil

No Description Available.

Date: April 1, 1975

Creator: Braski, D. N. & Schaffhauser, A. C.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Importance of billet microstructure in the hot extrusion of 2% Ti-Hastelloy N

The successful hot extrusion of billets of Ti-Hastelloy N (13 percent Mo, 7 percent Cr, 2 percent Ti, 0.06 percent C, 87.94 percent Ni) into tube shells and followed by cold drawing into 19-mm-OD (0.75-in.) tubing depends largely on the billet microstructure. It was imperative that the preheat annealing treatment given directly before hot extrusion be designed to uniformly dissolve most of the MC-type carbide particles. A 101.6-mm-diam x 304.8-mm-long (4 x 12-in.) billet required a preheat of 4… more

Date: May 1, 1977

Creator: Braski, D. N. & McDonald, R. E.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Characterization of SiC coatings on HTGR fuel particles: preliminary report

Fuel particles for the HTGR contain a layer of pyrolytic silicon carbide to act as a pressure vessel and fission product barrier. The SiC is deposited by the thermal decomposition of methyltrichlorosilane (CH/sub 3/SiC/sub 3/ or MTS) in an excess of hydrogen. Coatings deposited at temperatures from 1500 to 1700/sup 0/C and coating rates of 0.4 to 1.2 ..mu..m/min have been studied by optical microscopy, x-ray diffraction, electron microscopy, and density measurements. Transmission electron micro… more

Date: August 1, 1979

Creator: Lauf, R. J.; Braski, D. N. & Tennery, V. J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Resistance of (Fe,Ni)/sub 3/V long-range-ordered alloys to radiation damage

The (Fe,Ni)/sub 3/V long-range-ordered (LRO) alloys (path D) are being developed at ORNL for possible application as a first-wall material for a fusion reactor. Alloys with different Fe/Ni ratios have been screened for their resistance to radiation by irradiating them with 4 MeV Ni ions to 70 dpa at temperatures from 525 to 680/sup 0/C. Helium (8 at. ppM/dpa) and deuterium ions (28 at. ppM/dpa) were simultaneously injected to better simulate fusion reactor conditions. Alloy LRO-16 (31 wt % Ni) … more

Date: January 1, 1980

Creator: Braski, D. N.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Solidification behavior of austenitic stainless steel filler metals

Thermal analysis and interrupted solidification experiments on selected austenitic stainless steel filler metals provided an understanding of the solidification behavior of austenitic stainless steel welds. The sequences of phase separations found were for type 308 stainless steel filler metal, L + L + delta + L + delta + ..gamma.. ..-->.. ..gamma.. + delta, and for type 310 stainless steel filler metal, L ..-->.. L + ..gamma.. ..-->.. ..gamma... In type 308 stainless steel filler metal, ferrit… more

Date: February 1, 1980

Creator: David, S. A.; Goodwin, G. M. & Braski, D. N.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Resistance of (Fe, Ni)/sub 3/V long-range-ordered alloys to neutron and ion irradiation

A series of (Fe, Ni)/sub 3/V long-range-ordered alloys were irradiated with neutrons in the Oak Ridge Research Reactor (ORR) and with 4 MeV Ni ions at temperatures above 250/sup 0/C. The displacement damage levels for the two irradiations were 3.8 and 70 dpa, and the helium levels were 29 and 560 at. ppM, respectively. Irradiation in ORR generally increased the yield strength and lowered the ductility of an LRO alloy, but produced relatively little swelling. The LRO alloys retained their long-r… more

Date: January 1, 1981

Creator: Braski, D. N.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Interaction of noble-metal fission products with pyrolytic silicon carbide

Fuel particles for the High-Temperature Gas-Cooled Reactor (HTGR) contain layers of pyrolytic carbon and silicon carbide, which act as a miniature pressure vessel and form the primary fission product barrier. Of the many fission products formed during irradiation, the noble metals are of particular interest because they interact significantly with the SiC layer and their concentrations are somewhat higher in the low-enriched uranium fuels currently under consideration. To study fission product-… more

Date: January 1, 1982

Creator: Lauf, R. J. & Braski, D. N.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Improved swelling resistance for PCA austenitic stainless steel under HFIR irradiation through microstructural control

Six microstructural variants of Prime Candidate Alloy (PCA) were evaluated for swelling resistance during HFIR irradiation, together with several heats of type 316 stainless steel (316). Swelling was negligible in all the steels at 300/sup 0/C after approx. 44 dpa. At 500 to 600/sup 0/C 25%-cold-worked PCA showed better void swelling resistance than type 316 at approx. 44 dpa. There was less swelling variability among alloys at 400/sup 0/C, but again 25%-cold-worked PCA was the best. Microstruc… more

Date: January 1, 1983

Creator: Maziasz, P. J. & Braski, D. N.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Microstructural design of PCA austenitic stainless steel for improved resistance to helium embrittlement under HFIR irradiation

Several variants of Prime Candidate Alloy (PCA) with different preirradiation thermal-mechanical treatments were irradiated in HFIR and were evaluated for embrittlement resistance via disk-bend tensile testing. Comparison tests were made on two heats of 20%-cold-worked type 316 stainless steel. None of the alloys were brittle after irradiation at 300 to 400/sup 0/C to approx. 44 dpa and helium levels of 3000 to approx.3600 at. ppm. However, all were quite brittle after similar exposure at 600/s… more

Date: January 1, 1983

Creator: Maziasz, P. J. & Braski, D. N.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Microstructure and bend ductility of a (Fe,Ni)/sub 3/V ordered alloy irradiated in HFIR

Disks of a (Fe,Ni)/sub 3/V long-range-ordered alloy were irradiated in the High Flux Isotope Reactor to 10, 21, and 42 dpa and helium levels of 1000, 2700, and 6000 at. ppM, respectively. The irradiation temperatures were 300, 400, 500, and 600/sup 0/C. The alloy remained ordered under all conditions. Swelling of the alloy was low with a peak of 1.3% occurring at 500/sup 0/C. Severe embrittlement and intergranular fracture occurred after 10 dpa at 600/sup 0/C and extended to lower temperatures … more

Date: January 1, 1983

Creator: Braski, D. N.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Tensile properties of unirradiated PCA from room temperature to 700/sup 0/C

The tensile properties of Prime Candidate Alloy (PCA) austenitic stainless steel after three different thermomechanical treatments were determined from room temperature to 700/sup 0/C. The solution-annealed PCA had the lowest strength and highest ductility, while the reverse was true for the 25%-cold-worked material. The PCA containing titanium-rich MC particles fell between the other two heats. The cold-worked PCA had nearly the same tensile properties as cold-worked type 316 stainless steel. … more

Date: January 1, 1983

Creator: Braski, D. N. & Maziasz, P. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Modified tritium trick technique for doping vanadium alloys with helium

A modified tritium trick technique was used to implant three different levels of /sup 3/He in V-15Cr-5Ti (wt %) and Vanstar-7 specimens before irradiation in the Fast Flux Test Facility (FFTF). The modifications include: (1) wrapping of the specimens with tantalum foil to minimize oxygen contamination, and (2) a 400/sup 0/C decay-time treatment to prevent vanadium tritide formation and to produce a /sup 3/He bubble distribution similar to that produced during elevated temperature irradiation. P… more

Date: January 1, 1984

Creator: Braski, D. N. & Ramey, D. W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Effect of neutron irradiation on the tensile properties and microstructure of several vanadium alloys

Specimens of V-15Cr-5Ti, VANSTAR-7, and V-3Ti-1Si were encapsulated in TZM tubes containing /sup 7/Li to prevent interstitial pickup and irradiated in FFTF (MOTA experiment) to a damage level of 40 dpa. The irradiation temperatures were 420, 520, and 600/sup 0/C. For a better simulation of fusion reactor conditions, helium was preimplanted in some specimens using a modified version of the ''tritium trick.'' The V-15Cr-5Ti alloy was most susceptible to irradiation hardening and helium embrittlem… more

Date: January 1, 1986

Creator: Braski, D. N.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Effect of neutron irradiation on vanadium alloys

Neutron-irradiated vanadium alloys were evaluated for their susceptibility to irradiation hardening, helium embrittlement, swelling, and residual radioactivity, and the results were compared with those for the austenitic and ferritic stainless steels. The VANSTAR-7 and V-15Cr-5Ti alloys showed the greatest hardening between 400 and 600/sup 0/C while V-3Ti-1Si and V-20Ti had lower values that were comparable to those of ferritic steels. The V-15Cr-5Ti and VANSTAR-7 alloys were susceptible to hel… more

Date: January 1, 1986

Creator: Braski, D. N.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Effect of preinjected helium on the response of V-20Ti pressurized tubes to neutron irradiation

Vanadium-205 titanium tubes, pressurized to stresses of 34 and 39 MPa, were irradiated in the Experimental Breeder Reactor (EBR-II) at 700/sup 0/C to a displacement damage level of 22 dpa. Sections of the tubes were injected with 15 appM He prior to irradiation to determine ethe effect of helium on the microstructural and creep response of this alloy to irradiation. It was found that helium promoted cavity formation, primarily within existing precipitates, but total swelling remained low. Heliu… more

Date: January 1, 1986

Creator: Vitek, J. M.; Braski, D. N. & Horak, J. A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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The effect of neutron irradiation on the tensile properties and microstructure of several vanadium alloys. [Viewgraphs]

This paper contains viewgraphs describing the effects of neutron irradiation on the tensile properties and microstructure of vanadium alloys in first wall fusion reactors. A tritium trick experiment was used to study the helium embrittlement and the stresses and strains on these materials in a controlled environment. (LSP)

Date: January 1, 1987

Creator: Braski, D. N.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

The postirradiation tensile properties and microstructure of several vanadium alloys

Tensile specimens of V-15Cr-5Ti, Vanstar-7, V-3Ti-1si, and V-20Ti were irradiated at 420)degrees)C in FFTF-MOTA to a damage level of 82 dpa. Helium was preimplanted to levels up to 480 appm in selected specimens using a modified tritium trick. Irradiation hardening was the dominant effect influencing the postirradiation tensile properties, and it markedly increased the yield strength and reduced the total elogation. The V-15Cr-5Ti alloy was very sensitive to helium embrittlement, but Vanstar-7 … more

Date: January 1, 1988

Creator: Braski, D. N.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Vanadium alloys with improved resistance to helium embrittlement

A series of experimental vanadium alloys have been designed with small MC-type carbides in their microstructures to trap helium produced during neutron irradiation, thereby reducing helium embrittlement. The tensile properties and fabricability of the alloys were strongly influenced by the amounts of MC-forming-elements, especially carbon. Alloys with 0.05 and 0.10 wt % carbon exhibited slightly lower yield strengths at 420 to 600{degree}C than vanadium alloys such as V-5Cr-5Ti, Vanstar-7, V-3T… more

Date: January 1, 1990

Creator: Braski, D. N.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Proceedings of the fourth annual conference on fossil energy materials

The Fourth Annual Conference on Fossil Energy Materials was held in Oak Ridge, Tennessee, on may 15--17, 1990. The meeting was sponsored by the US Department of Energy's Office of Fossil Energy through the Advanced Research and Technology Development (AR TD) Materials Program, and ASM International. The objective of the AR TD Materials Program is to conduct research and development on materials for longer-term fossil energy applications as well as for generic needs of various fossil fuel techno… more

Date: August 1, 1990

Creator: Judkins, R.R. & Braski, D.N. (comps.)

Item Type: Article

Partner: UNT Libraries Government Documents Department

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The in-situ fracture and Auger analysis of Nicalon fibers

A technique has been developed to fracture irradiated Nicalon SiC fibers in a Scanning Auger Microprobe (SAM) and analyze the fracture surfaces without contaminating the specimen chamber. The technique, which was evaluated using as-received fibers, requires only minor modification of two standard specimen holders and should be applicable to other fibers or materials that can be broken under low loads in bending. The technique is simple, rapid, reduces beam charging, and eliminates the need for … more

Date: September 1, 1994

Creator: Braski, D. N. & Osborne, M. C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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XPS study of Ni-Fe manganite thermistor material

The resistivity of the as-fabricated thermistor material, nickel-iron-manganite, changes during initial aging in the temperature range of 150-300{degrees}C before becoming stable. X-ray photoelectron spectroscopy (XPS) was used to determine if any valency change or chemical shift of the cations or oxygen occurred after aging. The goal of the study was to identify any ionic changes that might affect thermistor stability. The only observed changes in 2p{sub 3/2} peaks due to aging were those rela… more

Date: March 1, 1995

Creator: Braski, D. N.; Osborne, N. R. & Zurbuchen, J. M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Au microstructure and the functional properties of Ni/Au finishes on ceramic IC packages

Ni/Au plated finishes used on thick-film metallized multilayer ceramic packages for integrated circuits must meet functional requirements such as bondability, sealability, and solderability. Their ability to do so is dependent, among other things, on the ability of the Au deposit to inhibit the grain boundary diffusion and subsequent surface oxidation of Ni. In this study, the relation between functional performance, Ni diffusionr ate, and Au microstructure was examined. Extent of Ni diffusion … more

Date: December 31, 1995

Creator: Winters, E. D.; Baxter, W. K.; Braski, D. N. & Watkins, T. R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Environmental aging degradation in continuous fiber ceramic composites

The thermal stability of two-continuous fiber ceramic composites (CFCC`s) has been assessed. A Nicalon/CaO-Al{sub 2}O{sub 3}-SiO{sub 2} (CAS) glass-ceramic composite has been subjected to unstressed, oxidation heat treatments between 375 and 1200{degrees}C, after which the material was tested in flexure at room temperature. The static fatigue behavior of a chemical vapor infiltrated (CVI) Nicalon/SiC ceramic matrix composite has been assessed in air, between 425 and 1150{degrees}C, both with an… more

Date: December 31, 1995

Creator: Plucknett, K. P.; Lin, H. T.; Braski, D. N. & Becher, P. F.

Item Type: Article

Partner: UNT Libraries Government Documents Department