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

Abstract

Computational homogenization techniques are used to predict the mechanical behavior of metal-matrix composites made of Al₂O₃ 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 behavior 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 behavior. Local plastic strain rate localization phenomena around the particles are analyzed for the periodic and random situations.

Keywords:

• Al–Mg metal-matrix composite
• finite element
• Portevin-Le Chatelier effect

Acknowledgements

The authors thank F. NGuyen for providing pictures with the random distribution of particles and K. Madi for meshing these pictures. The authors wish to acknowledge the financial support provided through the European Community's Human Potential Programme under contract HPRN-CT-2002-00198, (DEFINO project), and the DFG (Deutsche Forschungsgemeinschaft).