Molecular dynamics investigation of dislocation pinning by a nanovoid in copper

TL;DR

This study uses molecular dynamics simulations to explore how nanovoids in copper influence dislocation pinning, revealing different behaviors for leading and trailing partials and the effects of void size and position.

Contribution

It provides new insights into the atomic-scale mechanisms of dislocation pinning by nanovoids in copper, highlighting differences between partials and the influence of void size and position.

Findings

Trailing partial depinning stress increases logarithmically with void radius.

Leading partial shows a crossover in depinning behavior at 1 nm void radius.

Pinning angle approaches zero for voids larger than 3 nm.

Abstract

Interactions between an edge dislocation and a void in copper are investigated by means of molecular dynamics simulation. The depinning stresses of the leading partial and of the trailing partial show qualitatively different behaviors. The depinning stress of the trailing partial increases logarithmically with the void radius, while that of the leading partial shows a crossover at 1 nm above which two partials are simultaneously trapped by the void. The pinning angle, which characterizes the obstacle strength, approaches zero when the void radius exceeds 3 nm. No temperature dependence is found in the critical stress and the critical angle. This is attributed to an absence of climb motion. The distance between the void center and a glide plane asymmetrically affects the pinning strength.