Role of density fluctuations in the relaxation of random dislocation systems

TL;DR

This paper investigates how density fluctuations influence the relaxation process of dislocation systems in crystals, using a scaling model validated by simulations, with limitations in multiple slip geometries.

Contribution

It introduces a scaling model for dislocation relaxation based on density fluctuation extinction, validated for single slip but not for multiple slip systems.

Findings

Model accurately predicts relaxation in single slip systems.

Density fluctuations diminish over time during relaxation.

Model fails to describe multiple slip geometries.

Abstract

We study the relaxation dynamics of systems of straight, parallel crystal dislocations, starting from initially random and uncorrelated positions of the individual dislocations. A scaling model of the relaxation process is constructed by considering the gradual extinction of the initial density fluctuations present in the system. The model is validated by ensemble simulations of the discrete dynamics of dislocations. Convincing agreement is found for systems of edge dislocations in single slip irrespective of the net Burgers vector of the dislocation system. It is also demonstrated that the model does not work in multiple slip geometries.