Plastic flow in polycrystal states in a binary mixture

TL;DR

This study uses molecular dynamics simulations to analyze plastic flow in sheared polycrystalline binary mixtures, revealing large stress fluctuations due to grain boundary sliding and cooperative particle motions.

Contribution

It introduces visualization methods for local crystal orientation and disorder, providing new insights into grain boundary dynamics under shear in binary mixtures.

Findings

Large stress fluctuations from grain boundary sliding

Cooperative particle motions release elastic energy

Visualization of local crystal orientation and disorder

Abstract

Using molecular dynamics simulation we examine dynamics in sheared polycrystal states in a binary mixture containing 10% larger particles in two dimensions. We find large stress fluctuations arising from sliding motions of the particles at the grain boundaries, which occur cooperatively to release the elastic energy stored. These dynamic processes are visualized with the aid of a sixfold angle $\alpha_j(t)$ representing the local crystal orientation and a disorder variable $D_j(t)$ representing a deviation from the hexagonal order for particle $j$.