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in subjects: "Crystal Defects"

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Diffuse x-ray scattering studies of n and e/sup -/-irradiated Ni and dilute Ni alloys

Pure Ni and dilute NiSi and NiGe alloys were irradiated at 6 K with either fast neutrons or 3 MeV electrons. The resulting defect structures were studied using diffuse x-ray scattering methods after different annealing treatments. For both types of irradiation of pure Ni, large interstitial and vacancy dislocation loops developed on annealing. In contrast, interstitial agglomerates in a NiSi/sub .01/ alloy contained no more than approx. =10 interstitials, and few vacancy loops were observed. Co… more

Date: August 1, 1986

Creator: Averback, R. S. & Ehrhart, P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Sixth quarterly report of research on Cu/sub x/S--(Cd,Zn)S photovoltaic solar energy converters

Progress is reported on the growth of single crystal and polycrystalline CdS and (Cd,Zn)S containing different densities and types of structural defects for use in experimental photovoltaic cells. Hall mobility measurements have been made as a first step towards studying the effects of various structural defects on electrical parameters. Experimental cells have been made by the solid state reaction between (Cd,Zn)S and CuCl in order to permit current--voltage--temperature and spectral response … more

Date: October 1, 1978

Creator: Chin, B.L.; Sindelar, L.E. & Washburn, J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Atomic structures and compositions of interfaces

This research program focuses on an experimental study of the structure and chemistry of metal/metal oxide internal interfaces; the latter are mainly created, although not exclusively, by internal oxidation of binary or ternary metal alloys that are solid-solution phases prior to the internal oxidation treatment. The principal research tools are transmission electron microscopy (TEM), high resolution microscopy (HREM), analytical electron microscopy (AEM) and atom-probe field-ion microscopy (AP… more

Date: September 1, 1990

Creator: Seidman, D.N. (Northwestern Univ., Evanston, IL (United States). Dept. of Materials Science and Engineering) & Merkle, K.L. (Argonne National Lab., IL (United States))

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Tilt grain boundaries in YBa sub 2 Cu sub 3 O sub 7-x thin films

Grain boundaries in YBa{sub 2}Cu{sub 3}O{sub 7-x} superconductor thin films grown on (001) MgO by metal-organic chemical vapor deposition (MOCVD) have been characterized using transmission electron microscopy (TEM) and high-resolution electron microscopy (HREM). It was found that the YBa{sub 2}Cu{sub 3}O{sub 7-x} thin films were highly textured with the c axes, or (001) orientation, nearly parallel between grains and perpendicular to the MgO substrate. A majority of the grain boundaries are low… more

Date: July 1, 1990

Creator: Gao, Y.; Bai, G.; Chang, H. L. M.; Merkle, K. L. & Lam, D. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Cadmium sulfide/copper sulfide heterojunction cell research: critical studies in materials and durability. Quarterly progress report No. 3, January 1-March 31, 1980

Characterization of the CdS and (CdZn)S substrate material has continued. The morphological differences between heterojunctions made by solid and solution reaction processes have been further detailed. The results of cell stability testing under open circuit and 0.3V loading are reported.

Date: October 1, 1980

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Cadmium sulfide/copper sulfide heterojunction cell research: critical studies in materials and durability. Quarterly progress report No. 2, October 1-December 31, 1979

A systematic comparison between the CdS grain size determined by Transmission Electron Microscopy and by Scanning Electron Microscopy of etched surfaces is being carried out. It is found that the etching technique gives a good estimate of the true grain size. Discontinuities in the Cu/sub 2/S film produced by solution reaction have been studied by TEM after stripping from the CdS substrate. The various types of Cu/sub 2/S intrusions which can arise have been examined using SEM for material prod… more

Date: April 1, 1980

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Defect structures in YBa/sub 2/Cu/sub 3/O/sub 7-x/ produced by electron irradiation

Defect structures in YBa/sub 2/Cu/sub 3/O/sub 7-x/ produced by electron irradiation at 300/sup 0/ K were investigated by transmission electron microscopy. Threshold energies for the production of visible defects were determined to be 152 keV and 131 keV (+- 7 keV) in directions near the a and b (b > a) axes (both perpendicular to c, the long axis in the orthorhombic structure), respectively. During above threshold irradiations in an electron flux of 3 x 10/sup 18/ cm/sup -2/ s/sup -1/, extended… more

Date: December 1, 1987

Creator: Kirk, M.A.; Baker, M.C.; Liu, J.Z.; Lam, D.J. & Weber, H.W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Electron beam induced oxygen in YBa sub 2 Cu sub 3 O sub 7-x superconductors

Thin foils of bulk YBa{sub 2}Cu{sub 3}O{sub 7-x} (YBCO) superconductors were subjected to electron irradiation in a Transmission Electron Microscope (TEM). The resulting disordering of the oxygen atoms and vacancies in the Cu-O planes was monitored by measuring the splitting of the (110) diffraction spots in the (001) diffraction pattern. Samples were irradiated at 83K with 100, 150, 200 and 300kV electrons. The 100kV electrons did not cause any disordering, even after prolonged irradiation. Th… more

Date: January 1, 1989

Creator: Basu, S.N.; Roy, T.; Mitchell, T.E. & Nastasi, M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Silicon web process development. Annual report

During this reporting period significant milestones have been met. A new barrier crucible design which consistently maintains melt stability over long periods of time has been successfully tested and used in long growth runs. The pellet feeder for melt replenishment was operated continuously for growth runs of up to 17 hours (a one day growth cycle). The liquid level sensor comprising a laser/sensor system was operated, performed well, and meets the requirements for maintaining liquid level hei… more

Date: June 30, 1980

Creator: Duncan, C. S.; Seidensticker, R. G.; McHugh, J. P.; Hill, F. E.; Skutch, M. E.; Driggers, J. M. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Electron microscopy of ceramic superconductors

The critical current Jc is at least as important as Tc (transition temperature) for applications in superconducting materials. Jc is strongly dependent on microstructure and, in consequence, electron microscopy will continue to be important in the development of practical ceramic superconductors. We will review the progress that has been made over the past year or so in studying the superconductors by electron microscopy techniques of all kinds--conventional, high resolution, analytical, etc. A… more

Date: January 1, 1988

Creator: Mitchell, T.E. & Roy, T.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Anisotropic shift of the irreversibility line by neutron irradiation

The irreversibility line of high-{Tc} superconductors is shifted considerably by irradiating the material with fast neutrons. The anisotropic and non-monotonous shift is qualitatively explained by a simple model based on an interaction between three pinning mechanisms, the intrinsic pinning by the ab-planes, the weak pinning by the pre-irradiation defect structure, and strong pinning by neutron induced defect cascades. A correlation between the cascade density and the position of the irreversib… more

Date: September 1, 1991

Creator: Sauerzopf, F.M.; Wiesinger, H.P.; Weber, H.W. (Atominstitut der Oesterreichischen Universitaeten, Vienna (Austria)); Crabtree, G.W.; Frischherz, M.C. & Kirk, M.A. (Argonne National Lab., IL (United States))

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Evidence for shallow positron traps in a neutron-irradiated Al single crystal

Variable energy positrons have been used to determine the dependence on temperature of positron diffusion out of a neutron-irradiated single crystal of Al. The results are interpreted in the context of a one-dimensional diffusion model which includes bulk annihilations as well as trapping at voids and other microstructural defects in the bulk material by way of a removal rate kappa/sub eff/ of freely diffusing positrons. The data show a strongly negative dependence on temperature below 125/sup … more

Date: January 1, 1982

Creator: Schultz, P. J.; MacKenzie, I. K.; Lynn, K. G.; West, R. N. & Snead, C. L. Jr.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Photoelectronic properties of zinc phosphide crystals, films and heterojunctions. Quarterly progress report No. 1, February 26-June 30, 1979

A closed tube method has been developed for the synthesis of Zn/sub 3/P/sub 2/ from the elements which eliminates the potential dangers associated with high P pressures. Subsequent materials synthesis will be done routinely by this method. Initial efforts at single crystal growth of Zn/sub 3/P/sub 2/ from this material yielded polycrystalline material because of nucleation along the walls of the tube. Techniques for improving the situation are being tested. Wafers of large-grain polycrystaline … more

Date: July 1, 1979

Creator: Bube, R.H.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Interface stability and defect formation during crystal growth

Unidirectional solidification experiments have been carried out in organic crystals with the aim of improving our knowledge on the effects of constraints on the interface morphology and to increase our understanding of the growth of anisotropic materials. The experimental information shows that lateral constraints such as a sharp change in the cross-sectional area in the solid liquid interface path, can produce important changes in the microstructure if the interface morphology is planar, cellu… more

Date: January 8, 1991

Creator: Fabietti, L.M.R.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Materials property measurements

An in-depth review of the measurement techniques that could be used in materials characterization is presented. The measurement techniques to non-destructively determine the in-service or time-related aging of materials considered include ultrasonic velocity and attenuation, eddy current conductivity, neutron scattering and absorption, conventional and tomographic imaging for ultrasonic and radiation imaging, x-ray scattering, thermal impedance, and magnetic hysteresis. The three sections of th… more

Date: April 19, 1990

Creator: Boyd, D. M.; Green, E. R.; Doctor, S. R. & Good, M. S.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Microstructural studies of advanced austenitic steels

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: Report

Partner: UNT Libraries Government Documents Department

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Defect characterization with positron annihilation. [Review]

Positron annihilation in metal crystals is reviewed. A brief introduction to the positron annihilation technique is presented first. Then the ability of the positron technique to perform microstructural characterization of four types of lattice defects (vacancies, voids, dislocations, grain boundaries) is discussed. It is frequently not possible to obtain samples that contain only one type of defect in nonnegligible concentrations. Such situations exist for some alloys and for fatigued metal sa… more

Date: January 1, 1980

Creator: Granatelli, L & Lynn, K G

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Positron annihilation in solid and liquid Ni

New techniques have been developed for the study of metals via positron annihilation which provide for the in-situ melting of the samples and subsequent measurements via Doppler broadening of positron-annihilation radiation. Here we report these metods currently in use at our laboratory; ion implantation of /sup 58/Co and the use of Al/sub 2/O/sub 3/ crucibles for in-situ melting followed by the decomposition of the Doppler-broadened spectrum into a parabolic and a Gaussian component. Our earli… more

Date: March 1, 1982

Creator: Fluss, M. J.; Smedskjaer, L. C.; Chakraborty, B. & Chason, M. K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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The effect of crystal structure stability on the mobility of gas bubbles in intermetallic uranium compounds

Irradiation experiments with certain low-enrichment, high-density, uranium-base intermetallic alloys that are candidate reactor fuel materials, such as U/sub 3/Si and U/sub 6/Fe, have revealed extraordinarily large voids at low and medium fuel burnup. This phenomenon of breakaway swelling does not occur in other fuel types, such as U/sub 3/Si/sub 2/ and UAl/sub 3/, where a distribution of relatively small and stable fission gas bubbles forms. In situ transmission electron microscope observation… more

Date: January 1, 1988

Creator: Rest, J.; Hofman, G. L. & Birtcher, R. C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Defects in metal crystals. Progress report, May 1, 1975--April 30, 1976. [W--Re; Pt--Au; Mo--Ti]

Emphasis was on use of different irradiating species (300-700 eV Xe/sup +/ ions, 20-30 keV W/sup +/ ions, 20-30 keV Mo/sup +/ ions, and fast neutrons) to introduce both vacancies and interstitials in Mo, W, Au, Pt--(Au), W--(Re), Mo(Ti), Ni/sub 4/Mo, and low-swelling and commercial 316 stainless steels. The following are reported: (A) an in-situ field-ion microscope study of ion-irradiated tungsten and tungsten alloys (W-Re) (recovery in Stages I and II); (B) a review of Stages I to IV of irrad… more

Date: February 1, 1976

Creator: Seidman, D. N.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Thermodynamic Study of Nonstoichiometric Cerium Dioxide.

No Description Available.

Date: January 1, 1972

Creator: Panlener, R. J. & Blumenthal, R. N.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Some Problems of the Detection of Self-Interstitial Atoms in Field Ion Microscope Images

No Description Available.

Date: January 1, 1972

Creator: Robinson, J. T.; Wilson, K. L. & Seidman, D. N.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Critical currents, magnetic relaxation, and microstructure in zone-melted YBa sub 2 Cu sub 3 O sub x

Extruded YBa{sub 2}Cu{sub 3}O{sub x} wires have been zone-melted to develop highly textured microstructures. The zone-melted wires exhibit large magnetic hysteresis and transport J{sub c} values relative to conventional bulk YBa{sub 2}Cu{sub 3}O{sub x}. Transmission electron microscopy observations indicate unique grain boundary features which are likely to be responsible for reduced weak-link effects. Large amounts of intragranular defects such as dislocations and Y{sub 2}BaCuO{sub 5} particle… more

Date: January 1, 1990

Creator: Shi, Donglu; Chen, J.G.; Xu, Ming; Goretta, K.C. (Argonne National Lab., IL (USA)); McGinn, P.J. & Chen, W.H. (Notre Dame Univ., IN (USA))

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Influence of point defects on grain boundary diffusion in oxides

The influence of point defects on grain boundary diffusion of Co ions in NiO was studied using polycrystalline films and bicrystals. Grain boundary diffusion was studied at 750 C at oxygen partial pressure. Two diffusion regions were found. At low oxygen pressures, extrinsic diffusion was observed. Above oxygen pressure of 10{sup {minus}7}, influence of intrinsic point defects was detected. It was determined that grain boundary diffusion was > 3 orders of magnitude faster than volume diffusion.… more

Date: March 15, 1991

Creator: Stubican, V. S.

Item Type: Report

Partner: UNT Libraries Government Documents Department