An experimental and numerical investigation of the behaviour of AA5083 aluminium alloy in presence of the Portevin-Le Chatelier effect

An experimental investigation of the Portevin-Le Chatelier (PLC) effect in the aluminium alloy AA5083-H116 is undertaken in this Study through five different tests involving round, prismatic and flat notched specimen geometries. Measurements based on strain gages and digital image correlation (DIC) are used to capture and characterize the spatio-temporal features of the PLC behaviour. Inhomogeneous deformation with various localization bands caused by the PLC effect is observed in all tests, and the band characteristics are measured. The McCormick elastic-viscoplastic constitutive relation, developed for metals exhibiting this type of dynamic strain aging, is then described in detail, before the various parameters required by the model are determined based on available material tests. The model is finally used in full-scale 3D numerical simulations of the physical tests using the explicit solver of the non-linear finite element code LS-DYNA. It will be shown that the numerical results are able to reproduce most of the experimentally observed phenomena with reasonable accuracy. However, if the model is used to study the micromechanical mechanisms controlling the macromechanical behaviour of materials exhibiting PLC effects (such as the band morphology), more advanced constitutive relations may be required. (C) 2008 Elsevier Ltd. All rights reserved.