Comportement Des Alumags Dilues En Déformation Plastique

Abstract

Plastic deformation behaviour of aluminium – magnesium dilute alloys. The stamping of some Al-Mg alloys could be a problem for the manufacture of metal parts. Indeed, one could experience an instability of the plastic flow, an appearance of a localized plastic strain and a deterioration of the ductility. In this work, the plastic deformation at room temperature in various Al-Mg dilute alloys whose the tensile curve presents serrated yielding of Poitevin – Le Chatelier (PLC) effect has been investigated. Using a close simulation of the stamping behaviour, through uniaxial tensile tests for different orientations with respect to the rolling direction, we show the effects of the solute content and heat treatments on the amplitude of the PLC instability and their influence on the ductility as a function of the strain rate. We also show that the solute content of these alloys is the responsible factor for a more or less heterogeneous plastic strain. However, it seems that the amplitude of the instability is not the only parameter determining certain characteristics of the plastic jerky flow such as the ductility and the resistance to failure.