Results 241 to 250 of about 59,310 (292)

Crystallography of dislocations and dislocation loops in deformed iron

Philosophical Magazine, 1964
Abstract Crystallographic analyses of dislocations and dislocation loops in deformed b.c.c. iron observed in the electron microscope have been carried out by applying the electron diffraction theory of contrast at dislocations. Dislocations in deformed iron are in the form of tangles, with interspersed clusters of dislocation loops, from the very first
S. M. Ohr, D. N. Beshers
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Residual image contrast of dislocation loops

Physica Status Solidi (a), 1978
The electron microscope images of large dislocation loops lying perpendicular to the electron beam are calculated by applying the image simulation technique. It is found that the residual double arc contrast arising from the g · b × u term exhibits asymmetry which is depth dependent.
J. Narayan, S. M. Ohr
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Dislocation loops in finite systems

Physical Review B, 1994
The distortions induced by dislocation loops are studied in finite systems. The influence of finite size, D, of the system, surface tension, and surface-bending elastic constant on the nematic-smectic (NA) phase transition is discussed. In thin freely suspended smectic liquid-crystal films the nematic-smectic transition temperature, ${\mathit{T}}_ ...
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Cooperative Nucleation of Shear Dislocation Loops

Physical Review Letters, 2002
The mean elastic interaction between randomly distributed transient subcritical shear loops of the same sign, formed in the presence of an applied shear stress, is the "image stress." This stress is proportional to the volume density of loops and has the same sign as the applied stress.
Y Q, Sun, P M, Hazzledine, P B, Hirsch
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The Interaction of Straight Dislocations with Dislocation Loops in an Anisotropic Material (Zinc)

Physica Status Solidi (a), 1984
The elastic interactions between straight dislocations and dislocation loops, both unsheared and sheared are studied for an isotropic and anisotropic material, zinc. The total interaction energy and total force between the interacting elements are computed for isotropic and anisotropic materials and conclusions made on the effect of the flexibility of ...
H. M. Eissa, M. M. El-Oker
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Dislocation loops in irradiated iron

Philosophical Magazine, 1963
IT has been suggested many times that the hardening of iron and steel on irradiation may result from the interaction of glide dislocations with dispersed clusters of point defects. Two observations of such clusters using the technique of transmission electron microscopy have been reported in the literature1,2.
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On the annealing of dislocation loops by climb

The Philosophical Magazine: A Journal of Theoretical Experimental and Applied Physics, 1966
Abstract It is pointed out that the ‘ideal source’ model of annealing of dislocation loops, recently discussed by Seidman and Balluffi, may overestimate the rate of annealing under emission limited conditions by a factor of about five as compared with the jog model of Friedel.
D. N. Seidman, R. W. Balluffi
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Energy of Polygonal and Elliptical Dislocation Loops

physica status solidi (b), 1966
AbstractA general expression for the elastic strain energy of an arbitrary N‐sided planar polygonal dislocation loop is obtained from the stress field of dislocation segments using isotropic elasticity. This expression can be used to approximate the energy of any curved dislocation loop to any degree of accuracy.
G. C. T. Liu, J. C. M. Li
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On the Determination of the Nature of Dislocation Loops

Philosophical Magazine, 1964
Abstract A simplication of the electron microscope method for determination of the nature of dislocation loops is described. Full determination of the relevant diffraction conditions and of the Burgers vectors of the loops are avoided and knowledge of the sense of inclination of the loops and of the rotations of image and diffraction pattern is not ...
B. Edmondson, G. K. Williamson
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Dislocation Loops in a‐Silicon Nitride

Journal of the American Ceramic Society, 1993
Thin foils of fully dense, but only partially transformed, hot pressed silicon nitride materials have been examined by high‐resolution transmisson electron microscopy. Large untransformed grains are seen to contain high densities of nanometer dimension, round or oval, textural features. Examination at high magnification shows thest
Chong‐Min Wang, Frank L. Riley, Francisco Castro, Iñigo Iturriza   +3 more
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