Strain localization and percolation of stable structure in amorphous solids

TL;DR

This study investigates how strain localization in amorphous solids depends on structural relaxation and strain rate, revealing a link to k-core percolation of quasi-crystal-like order and suggesting a microstructural length scale.

Contribution

It uncovers the relationship between strain localization, structural relaxation, and percolation phenomena in amorphous solids, introducing a microstructural length scale.

Findings

Higher strain rates increase localization in rapidly quenched samples.

More gradually quenched samples show decreased localization with higher strain rates.

Percolation of quasi-crystal-like order correlates with strain localization transition.

Abstract

Spontaneous strain localization occurs during mechanical tests of a model amorphous solid simulated using molecular dynamics. The degree of localization depends upon the extent of structural relaxation prior to mechanical testing. In the most rapidly quenched samples higher strain rates lead to increased localization, while the more gradually quenched samples exhibit the opposite strain rate dependence. This transition coincides with the k-core percolation of atoms with quasi-crystal-like short range order. The authors infer the existence of a related microstructural length scale.