Unstable plastic flow in the Al-2%Mg alloy, effect of annealing process

We have investigated the Portevin-Le Chatelier characteristics at room temperature in annealed and cold-rolled Al-2%Mg alloys. Consequences of annealing on localization features are analyzed in relation with dislocation structures obtained by transmission electron microscopy. We have shown that the heat treatment affects significantly the jerky flow, namely, the range of instability, the critical strain for the onset of serrations and the ductility of the alloy. We interpret our results in accordance with dynamic strain aging mechanisms. (C) 2012 Elsevier B.V. All rights reserved.