Avalanche correlations and stress-strain curves in discrete dislocation plasticity

TL;DR

This paper investigates the correlations and stress-strain behaviors in discrete dislocation plasticity, revealing how deformation history and dislocation pinning influence the material's response and the variability of stress-strain curves.

Contribution

It provides a detailed analysis of avalanche correlations and stress-strain curve shapes using 2D and 3D simulations, highlighting the effects of plastic deformation and dislocation pinning.

Findings

Correlations reduce scatter in stress-strain curves.

Severe plastic deformation diminishes memory effects.

Dislocation pinning influences deformation behavior.

Abstract

The sequence of deformation bursts during plastic deformation exhibits scale-free features. In addition to the burst or avalanche sizes and the rate of avalanches the process is characterized by correlations in the series which become manifest in the resulting shape of the stress-strain curve. We analyze such features of plastic deformation with 2D and 3D simulations of discrete dislocation dynamics models and we show, that only with severe plastic deformation the ensuing memory effects become negligible. The role of past deformation history and dislocation pinning by disorder are studied. In general, the correlations have the effect of reducing the scatter of the individual stress-strain curves around the mean one.