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The role of dislocations in the flow stress grain size relationships
J. C. M. Li,Y. T. Chou +1 more
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In this article, the authors reviewed the effects of pile ups of dislocations on the relation between yield or flow stress and grain size, and some non-pileup theories of yielding are critically reviewed.Abstract:
Calculations involving pile ups of dislocations, both analytical and numerical, using either discrete dislocations or continuous distribution of dislocations of infinitesimal Burgers vectors, are reviewed in the light of their effects on the relation between yield or flow stress and grain size. The limitations of the pileup models are discussed and some nonpileup theories of yielding are critically reviewed also. More critical experiments are still needed to reveal the fundamental mechanicm of yielding.read more
Citations
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Short note Dynamic compression behaviour of tungsten powders consolidated by plasma pressure compaction
TL;DR: It has been generally believed that the ductility of tungsten can be increased by decreasing grain size to ultrafine levels (∼100 nm) as discussed by the authors, and it has been shown that tungstern powders of various average parti...
Journal ArticleDOI
On the role of non-equilibrium grain-boundary structure in the yield and flow stress of polycrystals
TL;DR: In this paper, the role of internal stresses induced by non-equilibrium grain boundaries (GBs) in the deformation behavior of polycrystals is studied, and two types of internal stress induced by GBs are considered: the stresses of triple-line disclination dipoles and those of disordered EGBD arrays.
Journal ArticleDOI
Behavior of Simple Screw Dislocation Arrays under an Applied Stress
K. Sadananda,M. J. Marcinkowski +1 more
TL;DR: In this article, a detailed numerical analysis has been made of the behavior of passing screw dislocation arrays on parallel slip planes as a first step in the development of a computer model of workhardening.
Journal ArticleDOI
Understanding the complete loss of uniform plastic deformation of some ultrafine-grained metallic materials in tensile straining
TL;DR: In this paper, a new macromechanical approach in combination with micromachanical considerations is used to explain this long-standing riddle in materials science and engineering, based on the yield point phenomenon and the stress state that develops at the Luders fronts.
Journal ArticleDOI
A micromechanical model for heterogeneous nanograined metals with shape effect of inclusions and geometrically necessary dislocation pileups at the domain boundary
TL;DR: In this article, the authors developed a new micromechanical model to predict the overall mechanical response of heterogeneous nanograined metals that consist of plastically deformable soft and hard domains.
References
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Book
Theory of Dislocations
John Price Hirth,Jens Lothe +1 more
TL;DR: Dislocations in Isotropic Continua: Effects of Crystal Structure on Dislocations and Dislocation-Point-Defect Interactions at Finite temperatures.
Journal ArticleDOI
The Deformation and Ageing of Mild Steel: III Discussion of Results
TL;DR: In this paper, an attempt is made to explain the observed phenomena in the yielding and ageing of mild steel, described in two previous papers, in the general terms of a grain-boundary theory.
Journal ArticleDOI
Singular Integral Equations. By N.I. Muskhelishvili. Translated fromthe 2nd Russian edition by J.R.M. Radok. Pp. 447. F1. 28.50. 1953. (Noordhoff, Groningen)
Journal ArticleDOI
Dislocation Velocities, Dislocation Densities, and Plastic Flow in Lithium Fluoride Crystals
W. G. Johnston,John J. Gilman +1 more
TL;DR: In this paper, the authors measured the velocities of individual dislocations in LiF, covering a range of twelve orders of magnitude in velocity, from 10−7 cm/sec to 105cm/sec.