Dislocation substructure induced by creep in molybdenum single crystals.
TL;DR: In this paper, the dislocation substructure formed during creep of molybdenum single crystals of axial orientation was examined by etch-pitting techniques after creep at 900 psi and 1650°C.
About: This article is published in Acta Metallurgica.The article was published on 1970-03-01. It has received 105 citations till now. The article focuses on the topics: Dislocation creep & Creep.
Citations
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01 Dec 1972
TL;DR: The effect of interfaces on mechanical properties is considered in this paper, with emphasis on dislocation mechanisms and the atomic scale structure of boundaries, and Elastic and plastic compatibilities at boundaries are treated.
Abstract: The effect of interfaces on mechanical properties is considered. Elastic and plastic compatibilities at boundaries are treated. Specific influences at both low and high temperatures are discussed, with emphasis on dislocation mechanisms and the atomic scale structure of boundaries.
562 citations
TL;DR: In this paper, a review of the recent experiments on microstructural changes occurring during the non-linear steady-state creep of single phase crystalline matter at elevated temperatures is presented.
Abstract: Over the past 15 years important advances have been made in the experimental study of the microstructural changes occurring during the non-linear steady-state creep of single phase crystalline matter at elevated temperatures. Curiously, although the results of these painstaking studies have gone a long way toward elucidating the mechanism of this phenomenon, they have been largely ignored in favour of some simple dislocation mechanisms that are not only inconsistent with these observations, but are also unable to describe correctly the known phenomenology. This review concentrates primarily on the recent experiments on microstructural alterations occurring during creep; however, it also surveys the many mechanistic models that attempt to describe this phenomenon, and finds them all deficient.
480 citations
TL;DR: In this article, a 3D mesoscopic model to simulate the collective dynamic behavior of a large number of curved dislocations of finite lengths has been developed for the purpose of analyzing deformation patterns and instabilities, including the formation of dislocation cell structures.
446 citations
TL;DR: In this paper, the average dislocation velocity depends linearly on the effective stress while the mobile dislocation density varies reciprocally with the internal stress, and the predicted recovery rate based on the measured internal stress dependence of the steady state creep rate agrees with Friedel's network growth model.
236 citations
TL;DR: In this article, a method of incorporating dislocation ensembles in the crystal plasticity constitutive framework, while accounting for their evolution during changing strain paths, is presented. But the model is not suitable for the analysis of polycrystalline deformation.
224 citations
References
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Book•
01 Jan 1968
TL;DR: Dislocations in Isotropic Continua: Effects of Crystal Structure on Dislocations and Dislocation-Point-Defect Interactions at Finite temperatures.
Abstract: Dislocations in Isotropic Continua. Effects of Crystal Structure on Dislocations. Dislocation-Point-Defect Interactions at Finite Temperatures. Groups of Dislocations. Appendixes. Author and Subject Indexes.
10,220 citations
1,299 citations
TL;DR: In this paper, the mechanical behavior of crystalline solids at elevated temperatures is discussed, including the creep properties of metals, solid solutions and two phase alloys, and the properties of two-phase alloys.
832 citations
TL;DR: In this article, a theory of steady-state creep is developed using Mott's mechanism of dislocation climb, which is assumed in the analysis that the rate-controlling process is the diffusion of vacancies between dislocations which are creating vacancies and those which are destroying them.
Abstract: A theory of steady‐state creep is developed using Mott's mechanism of dislocation climb. It is assumed in the analysis that the rate‐controlling process is the diffusion of vacancies between dislocations which are creating vacancies and those which are destroying them. The concentration of vacancies along a dislocation line is determined by setting the change in the free energy caused by a decrease or increase in the number of vacancies equal to the change in the elastic energy occuring during dislocation climb. The creep equation that results from the analysis is creep rate=const (σα/kT)exp(−Q/kT) where α is a constant (α∼3 to 4), Q is the activation energy of self‐diffusion, kT has its usual meaning, and σ is the stress. This equation is valid in the stress range from the critical shear stress to a stress about equal to 108 to 109 dynes/cm2. At larger stresses the creep rate increases much more rapidly with stress.
572 citations
TL;DR: In this paper, the slip systems observed in a number of crystal structures common amongst metals and simple ceramic materials are examined to see whether they allow the crystal to undergo an arbitrary strain without change of volume.
Abstract: The slip systems observed in a number of crystal structures common amongst metals and simple ceramic materials are examined to see whether they allow the crystal to undergo an arbitrary strain without change of volume. For most materials, other than f.c.c. and b.c.c. metals, there are insufficient independent slip systems. The condition under which cross slip can give rise to extra independent systems is stated. The results explain in a natural way recent experimental findings on the ductility of polycrystals with the sodium chloride structure.
411 citations