STRAIN-SOFTENING, SLIP LOCALIZATION AND PROPAGATION - FROM SIMULATIONS TO CONTINUUM MODELING

A continuum model is proposed for the Luders-like behaviour of single- crystals of dilute alloys undergoing strain softening. A constitutive form is established which incorporates a spatial coupling in the form of a second gradient. The latter takes into account the elastic intera ctions of dislocations of like sign, as suggested by earlier results o btained with the help of a numerical simulation. An approximate one-di mensional solution is proposed which yields three possible types of be haviour. uniform deformation, static and propagative strain localizati ons. The main properties of the Luders-like deformation, in particular the band velocity, are calculated and discussed as a function of the characteristic features of strain softening. Although this model is el aborated at a mesoscopic scale and does not take into account possible geometrical couplings, its results agree numerically with the existin g data on the dynamics of band propagation. Copyright (C) 1996 Acta Me tallurgica Inc.