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in subjects: "Crystal Defects"  
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Some considerations in the splitting of interstitial frank loops formed by irradiation

Description: The splitting of interstitial loops formed by irradiation is considered in detail. It is shown that they may split to form obtuse--angled single shear faults on the intersecting (111) planes. A detailed description of the splitting is given in which the interstitial Frank loop is viewed as being made up of perfect dislocation loop and two shears. The detailed description is then considered in the context of the formation of complex loops as are observed in quenching and irradiation studies. Exp… more
Date: May 1, 1975
Creator: Seshan, K.; Grilhe, J. & Washburn, J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Field-ion microscope studies of the defect structure of the primary state of damage of irradiated metals

Description: A review is presented of field ion microscope applications in studies of point defect distribution in irradiated metals. FIM results on the primary state of radiation damage in neutron and ion-irradiated iridium and tungsten, at both room-temperature and 78/sup 0/K, showed that it consists of: (1) isolated vacancies; (2) depleted zones; (3) compact vacancy clusters of voids; and (4) dislocation loops. The fraction of vacancies stored in the dislocation loops represented a small fraction of the … more
Date: January 1, 1975
Creator: Seidman, D. N.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Inhomogeneities in plastic deformation through dislocation glide

Description: Recent research involving the direct computer simulation of plastic deformation through planar dislocation glide suggests that plastic inhomogeneities such as the formation and growth of discrete slip bands are an inherent feature of deformation through glide. The sources of glide inhomogeneity are described and the influence of temperature, microstructural barriers, and applied stress on the heterogeneity of deformation in idealized crystals is discussed.
Date: September 1, 1975
Creator: Altintas, S.; Hanson, K. & Morris, J. W. Jr.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Theory of defect clustering and void formation

Description: This paper reviews the current understanding of the mechanisms and phenomena that form voids and dislocation structures as a consequence of displacement damage and concurrent annealing processes which tend to restore thermodynamic equilibrium. An attempt is made to provide a qualitative explanation for the effects of parameters on void formation and on the development of the dislocation structure during irradiation. Steady-state conditions, nucleation, swelling, and sink-annihilation probabilit… more
Date: January 1, 1975
Creator: Wiedersich, H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Oxygen potential of uranium--plutonium oxide as determined by controlled- atmosphere thermogravimetry

Description: The oxygen-to-metal atom ratio, or O/M, of solid solution uranium- plutonium oxide reactor fuel is a measure of the concentration of crystal defects in the oxide which affect many fuel properties, particularly, fuel oxygen potential. Fabrication of a high-temperature oxygen electrode, employing an electro-active tip of oxygen-deficient solid-state electrolyte, intended to confirm gaseous oxygen potentials is described. Uranium oxide and plutonium oxide O/M reference materials were prepared by i… more
Date: October 1, 1975
Creator: Swanson, G.C.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
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15 MeV neutron damage in Cu and Nb

Description: An investigation was made of high-energy neutron damage in Cu and Nb irradiated with approximately 15 MeV neutrons at the Oak Ridge Isochronous Cyclotron. The neutrons were generated by bombarding a thick Be target with 40- MeV deuterons resulting in a high energy neutron spectrum broadly peaked at 15 MeV. Single crystals of Cu and Nb were irradiated at room temperature to fluences of approximately 2 x 10$sup 17$ n/cm$sup 2$. The resulting loop-type defect clusters in the crystals were characte… more
Date: January 1, 1975
Creator: Roberto, J. B.; Narayan, J. & Saltmarsh, M. J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Positron annihilation in perfect and imperfect metals: a brief review

Description: The current renaissance of investigations of positron annihilation in solids has its origins in the observation that positrons interact strongly with certain crystal-lattice defects. Three properties of the annihilation process are being measured to gain information about the defects or about the local environment of the positron at the instant of its annihilation: positron lifetime, angular correlation of the two annihilation quanta, and Doppler broadening of the 511-keV annihilation line. Unt… more
Date: January 1, 1975
Creator: Goland, A.N.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Replacement collision sequences in metals

Description: The concept of radiation-induced defects traveling large distances by focussed collision sequences (focusons) without thermal activation has important consequences in radiation effect studies. The focussed collision sequences are of two types: (1) ''Silsbee focussing'' or momentum focussing which can cause defect pairs to form large distances from the primary knock-on and (2) focussed replacement collisions also called ''dynamic crowdions'' where mass transport causes a large separation between… more
Date: October 1, 1975
Creator: Blewitt, T. H.; Kirk, M. A. & Scott, T. L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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