Topic
Portevin–Le Chatelier effect
About: Portevin–Le Chatelier effect is a research topic. Over the lifetime, 677 publications have been published within this topic receiving 19146 citations. The topic is also known as: PLC effect & Savart-Masson effect.
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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.
570 citations
TL;DR: In this paper, the concentration of vacancies is increased by plastic deformations, which can cause strain ageing at room temperature, and the authors propose a method to deal with this problem.
Abstract: Substitutional solute atoms in aluminium usually diffuse too slowly to cause appreciable strain ageing at room temperature. However, if the concentration of vacancies is increased by plastic deform...
562 citations
TL;DR: 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.
551 citations
TL;DR: In this article, the rate sensitivity of the flow stress was investigated as a function of pre-strain for a commercial nickel alloy (INCONEL 600) and for polycrystalline Al-1% Mg. over a wide temperature range encompassing the regime of jerky flow.
517 citations
TL;DR: In this paper, a model for the critical strains associated with the Portevin-Le Châtelier effect (PLC) in terms of the strain dependence of the densities of mobile and forest dislocations is proposed.
Abstract: A model is proposed for the critical strains associated with the Portevin-Le Châtelier effect (PLC) in terms of the strain dependence of the densities of mobile and forest dislocations. The classical critical condition for the onset of the PLC effect, viz. that of vanishing of the strain rate sensitivity of flow stress under the influence of dynamic strain aging is reexamined. The analysis takes into account the strain dependence of a key quantity: the elementary strain produced when all mobile dislocations perform a successful thermally activated step through the forest obstacles. This elementary strain is estimated by studying a system of coupled differential equations for the evolution of the two densities. Results are obtained in semi-quantitative form and compared with available data. It is shown that the following effects are consistently explained: the occurrence of critical strains for the onset and termination of jerky flow, occasional observation of two PLC regimes within the same deformation curve, the behaviour of the critical strains at high strain rates and low temperatures and, possibly, the particular behaviour exhibited by some alloys at low strain rates and high temperatures. Consequences for the “friction” and “forest” models of dynamic strain aging are discussed.
466 citations