Fluctuation phenomena in crystal plasticity—a continuum model

Abstract

On microscopic and mesoscopic scales, plastic flow of crystals is\ncharacterized by large intrinsic fluctuations. Deformation by crystallographic\nslip occurs in a sequence of intermittent bursts ('slip avalanches') with\npower-law size distribution. In the spatial domain, these avalanches produce\ncharacteristic deformation patterns in the form of slip lines and slip bands\nwhich exhibit long-range spatial correlations. We propose a generic continuum\nmodel which accounts for randomness in the local stress-strain relationships as\nwell as for long-range internal stresses that arise from the ensuing plastic\nstrain heterogeneities. The model parameters are related to the local dynamics\nand interactions of lattice dislocations. The model explains experimental\nobservations on slip avalanches as well as the associated slip and surface\npattern morphologies.\n