Dislocation Glasses: Aging during Relaxation and Coarsening

TL;DR

This paper investigates the aging dynamics of dislocation systems in two dimensions, revealing glassy relaxation behaviors and the formation of cellular structures, with results comparable to experimental observations in polymers.

Contribution

It introduces numerical analysis of 2D dislocation systems showing two types of glassy behavior and aging phenomena, expanding understanding of dislocation dynamics without external stress.

Findings

Dislocations relax to disordered stable states with power-law dynamics.

Cellular structures form during climb and annihilation, with a dynamical exponent ~6.

Both correlation functions and diffusion coefficients exhibit aging.

Abstract

The dynamics of dislocations is reported to exhibit glassy properties. We study numerically various versions of 2d edge dislocation systems in the absence of externally applied stress. Two types of glassy behavior are identified: (i) dislocations gliding along randomly placed, but fixed, axes exhibit relaxation to their spatially disordered stable state; (ii) if both climb and annihilation is allowed, irregular cellular structures can form on a growing length scale before all dislocations annihilate. In all cases both the correlation function and the diffusion coefficient are found to exhibit aging. Relaxation in case (i) is a slow power law. In the transient process of (ii) the dynamical exponent z is about 6, which compares favorably to experiments on diblock co-polymers.