Dislocation interactions mediated by grain boundaries

TL;DR

This paper investigates how grain boundary deformation influences dislocation interactions in polycrystals, revealing modifications to stress fields and implications for strain avalanche behavior.

Contribution

It introduces a framework to analyze dislocation-grain boundary interactions considering boundary deformation, extending beyond rigid boundary assumptions.

Findings

Deformable grain boundaries alter dislocation stress fields.

Analytical and numerical methods quantify boundary effects.

Implications for avalanche statistics in polycrystals.

Abstract

The dynamics of dislocation assemblies in deforming crystals indicate the emergence of collective phenomena, intermittent fluctuations and strain avalanches. In polycrystalline materials, the understanding of plastic deformation mechanisms depends on grasping the role of grain boundaries on dislocation motion. Here the interaction of dislocations and elastic, low angle grain boundaries is studied in the framework of a discrete dislocation representation. We allow grain boundaries to deform under the effect of dislocation stress fields and compare the effect of such a perturbation to the case of rigid grain boudaries. We are able to determine, both analytically and numerically, corrections to dislocation stress fields acting on neighboring grains, as mediated by grain boundary deformation. Finally, we discuss conclusions and consequences for the avalanche statistics, as observed in polycrystalline samples.