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Investigation of Moisture-Induced Embrittlement of Iron Aluminides. Interim Report

Description: Alloy FA-129 undergoes an increase in crack propagation rate and a loss of fracture toughness in moisture-bearing and hydrogen gas environments. A similar effect is seen on ductility of FA-129 in tensile tests. The embrittling effect in air is attributed to oxidation of aluminum in the alloy by water vapor to produce Al{sub 2}O{sub 3} and hydrogen gas. Alloy FAP-Y, which is disordered and contains only 16 a%Al is embrittled by hydrogen gas in a manner similar to that of FA-129. However, laborat… more
Date: April 19, 1994
Creator: Castagna, A. & Stoloff, N. S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Metallographic and hardness examinations of TMI-2 lower pressure vessel head samples

Description: Fifteen steel samples were removed from the lower pressure vessel head of the damaged TMI-2 nuclear reactor to assess the thermal threat to the head posed by 15 to 20 metric tons of molten core debris relocating there during the accident. Full sections of thirteen of the samples and partial sections of the other two samples underwent hardness and metallographic examinations at the Idaho National Engineering Laboratory. These examinations have shown that eleven of the fifteen samples did not exc… more
Date: March 1, 1994
Creator: Korth, G. E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Individual and combined effects of chloride, sulfate, and magnesium ions on hydrated Portland-cement paste

Description: Ground water with a high concentration of magnesium ion is known to cause deterioration to portland cement concretes. A proposed mechanism for this deterioration process published previously involves an approximate 1:1 replacement of Ca ions by Mg ions in the crystalline phases of hydrated cement. The current study was undertaken to determine which ions, among magnesium, chloride, and sulfate, cause deterioration; whether their deleterious action is individual or interdependent; and to relate t… more
Date: March 1, 1994
Creator: Poole, T. S.; Wakeley, L. D. & Young, C. L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Progress report on conductive paints, December 1, 1993--February 28, 1994

Description: Paints were sprayed onto glass substrates and air dried or baked. Hardness was measured and found to be maximum at 300 C baking temperature. No measurable adhesion to delrin, teflon, or nylon was obtained; however, adhesion to Plexiglas was obtained and measured. 2 tabs, 2 figs.
Date: March 1, 1994
Creator: Soukup, R. J. & Ianno, N. J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Recent progress on ECVD Project. Progress report for 15 April--15 July 1994

Description: Recent experimental results obtained for enhanced CVD are reported. These experiments included: (1) the distribution of deposition rates of various powders on the substrate in the reactor; (2) comparison of deposition rates of CVD and enhanced CVD; (3) evaluation of the mechanical properties of ECVD with commercial powders and ultra fine powders produced by plasma vapor deposition method. Unlike the experiments conducted by Komiyama and co-worker where fine particles were generated in situ, in … more
Date: August 1, 1994
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Ion beam surface treatment: A new capability for surface enhancement

Description: The emerging capability to produce high average power (5--350 kW) pulsed ion beams at 0.2--2 MeV energies is enabling the authors to develop a new, commercial-scale thermal surface treatment technology called Ion Beam Surface Treatment (IBEST). This new technique uses high energy, pulsed ({<=}250 ns) ion beams to directly deposit energy in the top 2--20 micrometers of the surface of any material. The depth of treatment is controllable by varying the ion energy and species. Deposition of the ene… more
Date: July 1, 1994
Creator: Stinnett, R. W.; McIntyre, D. C.; Buchheit, R. G.; Neau, E. L.; Greenly, J. B.; Thompson, M. O. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Densification of nano-size powders. 1994 report

Description: Green compacts from a nano-size silicon nitride powder were fabricated having density up to 67% of theoretical at 2.8 GPa pressure using liquid nitrogen and pentane as compaction lubricant media. Pressureless sintering of these transparent samples did not promote further densification beyond that obtained for the green state. To further increase the density of these samples, a hot-pressing device was designed. In a series of experiments, hot-pressing of these samples at.0.5 to 1.0 GPa and 800 C… more
Date: June 1, 1994
Creator: Chen, W.; Malghan, S. G.; Dapkunas, J. S.; Piermarini, G.; Pechenik, A. & Danforth, S. C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

High-energy ion processing of materials for improved hardcoatings

Description: Research has been directed toward use of economically viable ion processing strategies for production and improvement of hardcoatings. Processing techniques were high-energy ion implantation and electron cyclotron resonance microwave plasma processing. Subject materials were boron suboxides, Ti-6Al-4V alloy, CoCrMo alloy (a Stellite{trademark}), and electroplated Cr. These materials may be regarded either as coatings themselves (which might be deposited by thermal spraying, plasma processing, e… more
Date: February 1, 1994
Creator: Williams, J. M.; Gorbatkin, S. M.; Rhoades, R. L.; Oliver, W. C.; Riester, L. & Tsui, T. Y.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Time dependent indentation testing at non-ambient temperatures utilizing the high temperature mechanical properties microprobe

Description: Time dependent indentation data for pure indium from {minus}100{degrees}C to 75{degrees}C is presented. The properties reported include hardness, indentation strain rate, stress exponent and apparent activation energy for creep. These properties were measured using a depth-sensing indentation system capable of performing experiments between {minus}100{degrees}C and 300{degrees}C in ultra-high vacuum. In addition, by employing laser interferometric techniques, this system can obtain displacement… more
Date: December 31, 1994
Creator: Lucas, B. N. & Oliver, W. C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Investigation of depth-area relationships associated with nanoindentations

Description: Determination of hardness from indentation testing requires the measurement of the contact area. For indents generated at very low loads (<20 mN) or shallow depths (<250 nm), optical methods do not have sufficient resolution. One approach utilized in current state-of-the-art mechanical properties microprobes (MPM) involves the measurement of indenter depth. Calculation of the plastic area then requires a relation between depth and contact area. This relation is generally derived either by assum… more
Date: October 1, 1994
Creator: Riester, L. & Ferber, M. K.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Deposition and properties of novel nitride superlattice coatings. Progress report, 28 September 1990--October 1994

Description: The major effort during this report period was to elucidate the hardening mechanisms in polycrystalline superlattices. Since the last progress report, the authors have been working on theoretical modeling of hardening mechanisms in superlattices and have carried out detailed studies of two new polycrystalline superlattice coatings, NbN/VN and CrN/TiN, which were produced using an opposed, dual-cathode, high-rate, reactive, unbalanced-magnetron sputtering system. Significant hardness enhancement… more
Date: October 1, 1994
Creator: Barnett, S. A.; Sproul, W. D. & Wong, M. S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Mechanical properties of nanophase metals

Description: Nanophase metals have grain-size dependent mechanical properties that are significantly different than those of their coarse-grained counterparts. Pure metals are much stronger and apparently less ductile than conventional ones; intermetallics are also strengthened, but they tend toward increased ductility at the smallest grain sizes. These property changes are primarily related to grain size limitations, but they are also affected by the large percentage of atoms in grain boundaries and other … more
Date: November 1994
Creator: Siegel, R. W. & Fougere, G. E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Strength anomaly in B2 FeAl single crystals

Description: Strength and deformation microstructure of B2 Fe-39 and 48%Al single crystals (composition given in atomic percent), which were fully annealed to remove frozen-in vacancies, have been investigated at temperatures between room temperature and 1073K. The hardness of as-homogenized Fe-48Al is higher than that of as-homogenized Fe-39Al while after additional annealing at 698K the hardness of Fe-48Al becomes lower than that of Fe-39Al. Fe-39Al single crystals slowly cooled after homogenizing at a hi… more
Date: December 31, 1994
Creator: Yoshimi, K.; Hanada, S.; Yoo, M.H. & Matsumoto, N.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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