Correlations of non-affine displacements in metallic glasses through the yield transition

TL;DR

This study investigates how non-affine displacements in metallic glasses correlate during shear deformation, revealing a shear transformation zone size in the elastic regime and a diverging length scale during shear band formation, supporting a phase transition perspective.

Contribution

It provides molecular dynamics evidence linking correlation lengths of displacements to shear transformation zones and shear band development in metallic glasses.

Findings

Correlation length in elastic regime matches shear transformation zone size

Correlation length becomes system-size dependent after yield

Supports yield as a first-order phase transition

Abstract

We study correlations of non-affine displacement during simple shear deformation of Cu-Zr bulk metallic glasses in molecular dynamics calculations. In the elastic regime, our calculations show exponential correlation with a decay length that we interpret as the size of a shear transformation zone in the elastic regime. This correlation length becomes system-size dependent beyond the yield transition as our calculation develops a shear band, indicative of a diverging length scale. We interpret these observations in the context of a recent proposition of yield as a first-order phase transition.