Finite element simulations of the Portevin-Le Chatelier effect in metal-matrix composites

Abstract : Computational homogenization techniques are used to predict the mechanical behaviour of metal matrix composites made of Al203 particles in a Al-3% Mg matrix exhibiting dynamic strain ageing. A simple strain ageing continuum model is identified to describe the Portevin--Le Chatelier effect observed in the bulk aluminium alloy. Periodic homogenization is shown to provide a correct description of the mechanical behaviour of the composite concerning the presence of serrations on the macroscopic stress--strain curve and the prediction of the critical strain. Finite Element simulations of random distributions of particles are also performed to confirm the prediction of the overall behaviour. Local plastic strain rate localization phenomena around the particles are analyzed for the periodic and random situations.