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in subjects: "Grain Boundaries"  
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Anisotropy of oxygen tracer diffusion in YBa sub 2 Cu sub 3 O sub 7-. delta. single crystals

Description: The crystal structure of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} strongly suggests that the diffusion of oxygen in this material will be highly anisotropic, with diffusion in the ab plane being much faster than diffusion parallel to the c axis, and this has been assumed in most analyses of diffusion in YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}. The present data confirm this hypothesis; the diffusion coefficient in the ab plane is several orders of magnitude greater than the diffusion coefficient along th… more
Date: September 1, 1989
Creator: Rothman, S. J.; Routbort, J. L.; Liu, J.-Z.; Downey, J. W.; Thompson, L. J.; Fang, Y. et al.
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Partner: UNT Libraries Government Documents Department
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Atomic matching across internal interfaces

Description: The atomic structure of internal interfaces in dense-packed systems has been investigated by high-resolution electron microscopy (HREM). Similarities between the atomic relaxations in heterophase interfaces and certain large-angle grain boundaries have been observed. In both types of interfaces localization of misfit leads to regions of good atomic matching within the interface separated by misfit dislocation-like defects. It appears that, whenever possible, the GB structures assume configurati… more
Date: January 1, 1989
Creator: Merkle, K.L. (Argonne National Lab., IL (USA))
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Partner: UNT Libraries Government Documents Department
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Characterization of nanophase materials by x-ray diffraction and computer simulation

Description: X-ray diffraction experiments on nanophase Pd have been performed with the primary goal of determining the nature of grain boundary structures in nanophase materials. A kinematical diffraction analysis has been developed to interpret x-ray {theta}--2{theta} data by comparing actual scans with scans produced by computer simulation. This simulation program has been used to explore the effects on diffracted intensity of a variety of microstructural and grain boundary structural parameters such as … more
Date: June 1, 1989
Creator: Eastman, J.A. & Thompson, L.J. (Argonne National Lab., IL (USA))
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Partner: UNT Libraries Government Documents Department
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The feasibility of welding of irradiated materials

Description: Helium was implanted into solution-annealed (SA) 316 stainless steel, 20% cold-worked (CW) 316 stainless steel and titanium-modified Primary Candidate Alloy (PCA) through tritium decay to levels ranging from 0.18 to 256 appm. Full penetration welds were then made on helium-doped materials using gas tungsten arc welding (GTAW) under fully constrained conditions. Intergranular heat-affected zone (HAZ) cracking was observed in all of the materials containing greater than 1 appm He. Electron micros… more
Date: January 1, 1989
Creator: Lin, H. T.; Chin, B. A. (Oak Ridge National Lab., TN (USA) & Auburn Univ., AL (USA). Dept. of Materials Engineering)
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Partner: UNT Libraries Government Documents Department
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Intergranular and interphase boundaries in ceramics

Description: Interfaces are of great importance in both electronic and structural ceramics. The microstructure and microchemistry of interfaces can be studied by transmission electron microscopy, both high resolution and analytical. Examples are taken from both intergranular and interphase boundaries in ceramics. The former include low angle, twin and 90/degree/ boundaries in YBa/sub 2/Cu/sub 3/O/sub 7/ superconductors. Interphase boundaries include epitactic layers of YBa/sub 2/Cu/sub 3/O/sub 7/on SrTiO/su… more
Date: January 1, 1989
Creator: Mitchell, T.E.; Roy, T. & Unal, O.
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Partner: UNT Libraries Government Documents Department
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High resolution energy loss research: Si compounds and ceramics

Description: Analytical and high resolution electron microscopes are used to investigate interfaces, grain boundaries and triple junctions in a number of materials. Interfaces between silicon carbide whiskers and either aluminum oxide or silicon nitride grains in two different ceramic matrix composites were found to be mostly crystalline, and did not contain a continuous amorphous phase. The amount of amorphous phase in these interfaces depended primarily on the amount of sintering aid used. Amorphous multi… more
Date: 1989
Creator: Carpenter, R.W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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APFIM (atom probe field-ion microscope) investigations of solute clustering and precipitation in irradiated RPV (reactor pressure vessel) steels

Description: After exposure to low and intermediate fluence neutron irradiation, a variety of reactor pressure vessel (RPV) steels, including A533B-type surveillance specimens, Gundremmigen KRB-A ex-service plate, and test reactor irradiated materials, have been analyzed in the atom probe field-ion microscope (APFIM). With this instrument, it is possible to characterize the ultrafine microstructural features associated with irradiation embrittlement. The statistical significance of the solute clustering has… more
Date: January 1, 1989
Creator: Burke, M. G.; Grant, S. P. & Miller, M. K.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Study of nanophase TiO/sub 2/ grain boundaries by Raman spectroscopy

Description: Raman spectra have been recorded for as-consolidated nanophase TiO/sub 2/ samples with differing grain sizes and on samples annealed in air at a variety of temperatures up to 1273 K. The nanophase samples with the smallest grain size, about 12 nm average diameter, could have 15-30% of their atoms in grain boundaries; nevertheless, the strong Raman-active lines representative of the rutile structure were found to dominate all of the observed spectra, independent of grain size and annealing treat… more
Date: January 1, 1989
Creator: Melendres, C.A.; Narayanasamy, A.; Maroni, V.A. & Siegel, R.W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Computer Modelling of Particle Limited Grain Growth and Its Experimental Verification

Description: Data from two simulations on particle limited grain growth are reported. For 3D simulations the same type of strong correlation between particles and grain boundaries previously found in 2D simulations was found with the limiting grain size scaling in 3D with (l/f){sup 0.31}. Very much higher particle correlation with grain boundaries and particularly with grain corners was obtained than expected for the random microstructure. The size distribution of the pinned grain structures showed consider… more
Date: January 1, 1989
Creator: Doherty, R. D.; Li, K.; Kashyup, K.; Rollett, A. D. & Anderson, M. P.
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Partner: UNT Libraries Government Documents Department
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An evaluation of electrochemical potentiokinetic reactivation techniques for in-service measurements on Type 304 stainless steel

Description: Electrochemical potentiokinetic reactivation (EPR) tests can be used to measure quantitatively the sensitization of Type 304 stainless steel. The single loop (SL) and double loop (DL) EPR techniques were compared as non-destructive methods for determining sensitization under both laboratory and simulated field environments. Measurements were performed on specimens heat-treated to produce levels of sensitization from no sensitization to heavy sensitization. At temperatures of 22/degree/C and 30/… more
Date: January 1, 1989
Creator: Stoner, K.J.
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Partner: UNT Libraries Government Documents Department
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Microstructural studies of advanced austenitic steels

Description: This report presents the first complete microstructural and analytical electron microscopy study of Alloy AX5, one of a series of advanced austenitic steels developed by Maziasz and co-workers at Oak Ridge National Laboratory, for their potential application as reheater and superheater materials in power plants that will reach the end of their design lives in the 1990's. The advanced steels are modified with carbide forming elements such as titanium, niobium and vanadium. When combined wit… more
Date: November 15, 1989
Creator: Todd, J. A. & Ren, Jyh-Ching
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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High resolution energy loss research: Si compounds and ceramics. Progress report, January 1, 1988--January 1, 1989

Description: Analytical and high resolution electron microscopes are used to investigate interfaces, grain boundaries and triple junctions in a number of materials. Interfaces between silicon carbide whiskers and either aluminum oxide or silicon nitride grains in two different ceramic matrix composites were found to be mostly crystalline, and did not contain a continuous amorphous phase. The amount of amorphous phase in these interfaces depended primarily on the amount of sintering aid used. Amorphous multi… more
Date: 1989
Creator: Carpenter, R. W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Storage of LWR (light-water-reactor) spent fuel in air

Description: An experimental program is being conducted at Pacific Northwest Laboratory (PNL) to determine the oxidation response of light-water-reactor (LWR) spent fuels under conditions appropriate to fuel storage in air. The program is designed to investigate several independent variables that might affect the oxidation behavior of spent fuel. Included are temperature (135 to 230{degree}C), fuel burnup (to about 34 MWd/kgM), reactor type (pressurized and boiling water reactors), moisture level in the air… more
Date: December 1, 1989
Creator: Thomas, L. E.; Charlot, L. A.; Coleman, J. E. (Pacific Northwest Lab., Richland, WA (USA)) & Knoll, R. W. (Johnson Controls, Inc., Madison, WI (USA))
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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High voltage/high resolution studies of metal and semiconductor interfaces

Description: The application of high resolution transmission electron microscopy to the study of homo- or hetero-phase interface structures requires specimens that meet stringent criteria. In some systems the necessary geometric imaging conditions are established naturally, thus greatly simplifying the analysis. This is illustrated for a diamond-hexagonal/diamond-cubic interface in deformed silicon, a {Sigma}99 tilt boundary in a pure aluminum bicrystal, and a germanium precipitate in an aluminum matrix. 13… more
Date: November 1, 1989
Creator: Westmacott, K. H. & Dahmen, U.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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In situ HVEM study of ion irradiation-induced grain growth in Au thin films

Description: In situ observations of 1.5 MeV Xe/sup +/ ion irradiated Au films at room temperature and at 150/degree/C reveal the evolution of grain growth: the average grain size increases by the mechanisms of grain boundary migration and grain coalescence. 10 refs., 4 figs.
Date: January 1, 1989
Creator: Liu, Joyce C.; Li, Jian; Mayer, J. W.; Allen, Charles W. & Rehn, Lynn E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Statistical model for grain boundary and grain volume oxidation kinetics in UO{sub 2} spent fuel

Description: This paper addresses statistical characteristics for the simplest case of grain boundary/grain volume oxidation kinetics of UO{sub 2} to U{sub 3}O{sub 7} for a fragment of a spent fuel pellet. It also presents a limited discussion of future extensions to this simple case to represent the more complex cases of oxidation kinetics in spent fuels. 17 refs., 1 fig.
Date: September 1, 1989
Creator: Stout, R. B.; Shaw, H. F. & Einziger, R. E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Chemistry and Materials Science Department annual report, 1988--1989

Description: This is the first annual report of the Chemistry & Materials Science (C&MS) Department. The principal purpose of this report is to provide a concise summary of our scientific and technical accomplishments for fiscal years 1988 and 1989. The report is also tended to become part of the archival record of the Department`s activities. We plan to publish future editions annually. The activities of the Department can be divided into three broad categories. First, C&MS staff are assigned by the matrix… more
Date: December 31, 1989
Creator: Borg, Richard J.; Sugihara, Thomas T.; Cherniak, Jay C. & Corey, Cara W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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