Fluctuation phenomena in crystal plasticity - a continuum model

TL;DR

This paper introduces a continuum model for crystal plasticity that captures the intrinsic fluctuations, slip avalanches, and resulting deformation patterns observed in crystalline materials, linking microscopic dislocation dynamics to macroscopic behavior.

Contribution

It presents a novel continuum framework incorporating randomness and long-range stresses to explain slip avalanches and deformation patterns in crystals.

Findings

Model reproduces power-law slip avalanche distributions.

Explains formation of slip lines and bands.

Aligns with experimental observations of surface patterns.

Abstract

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