Journal ArticleDOI
Theory of the effect of dynamic strain aging on mechanical properties
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In this paper, the authors described dynamic strain aging (DSA) in solid solutions as diffusion of solute atoms to mobile dislocations, temporarily arrested at obstacles, and calculated the dependence of the flow stress on strain rate, temperature, and strain in the presence of DSA.Abstract:
Dynamic strain aging (DSA) in solid solutions is described as diffusion of solute atoms to mobile dislocations, temporarily arrested at obstacles. As a consequence the solute concentration experienced locally by the dislocations depends on the time of arrest and the solute diffusion coefficient. Starting from this idea the dependence of the flow stress on strain rate, temperature, and strain in the presence of DSA is calculated. A criterion for the onset of serrated yielding is formulated. Finally the change in strain rate sensitivity due to DSA is calculated. The theory allows a qualitative and in some respects a quantitative comparison with experimental results of which some examples are given.read more
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Time distribution of stress drops, critical strain and crossover in the dynamics of jerky flow
K. Chihab,Claude Fressengeas +1 more
TL;DR: In this paper, the distribution in time of stress drops in the jerky flow of several Al-Mg alloys is investigated in velocity controlled tensile tests, in relation with the crossover from hopping to propagating bands.
Journal ArticleDOI
Size effects on plasticity in high-entropy alloys
TL;DR: The role of defect types as carriers of plasticity is evaluated and correlated with the frequently observed mechanical behavior peculiar to the breed of high-entropy alloys in this article, and the role of interfaces between crystallographically dissimilar lattices on small-scale deformation behavior is assessed.
Journal ArticleDOI
Relaxation oscillations and negative strain rate sensitivity in the portevin-Le chatelier effect
S. Rajesh,G. Ananthakrishna +1 more
TL;DR: This work addresses the issue of time scales and its connection to the negative strain rate sensitivity of the flow stress within the framework of a model for the jerky flow, and shows that the nature of the relaxational oscillations is a result of the atypical bent geometry of the slow manifold.
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The mechanism of critical strain and serration type of the serrated flow in Mg-Nd-Zn alloy
TL;DR: In this article, the critical strain for serrated flow and the critical stress for unpinning processes were defined, which give a better explanation to the variation tendency of two definitions in accordance with temperature.
Journal ArticleDOI
Occurrence of dynamic strain aging in Alloy 617M under low cycle fatigue loading
TL;DR: In this article, a low cycle fatigue (LCF) behavior of solution annealed Alloy 617M forging at 300, 573, 773 and 973 K was studied at a nominal strain rate of 3.10−3.1 s−1.
References
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Journal ArticleDOI
A model for the Portevin-Le Chatelier effect in substitutional alloys
TL;DR: In this article, the authors derived a model for the onset of the Portevin-Le Chatelier effect in substitutional alloys, based on the solute locking of dislocations temporarily arrested at obstacles in the glide path.
Journal ArticleDOI
Mathematics of the portevin-le chatelier effect
TL;DR: In this article, it is shown mathematically that the strain rate at any point in the tensile material must make jumps as a function of time, whenever the stress as the function of strain rate, for given strain, goes through a maximum and minimum.
Journal ArticleDOI
Serrated yielding and inhomogeneous deformation in Au(14at%Cu)
A. Wijler,J.Schade van Westrum +1 more
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The onset of serrated yielding in Au(Cu) alloys
TL;DR: In this article, the onset of serrated yielding in Au(Cu) alloys has been investigated as a function of strain rate, temperature, Cu concentration and initial state of order both in prequenched and furnace cooled specimens.