Size-independent Shear Band Formation in Amorphous Nanowires made from Simulated Casting

TL;DR

This study uses molecular dynamics simulations to show that shear band formation in amorphous nanowires is largely independent of size, influenced mainly by surface effects and the sample's relaxation process.

Contribution

It introduces a casting simulation routine for preparing amorphous nanowires and demonstrates size-independent shear band formation in samples as small as 15 nm.

Findings

Shear bands form in nanowires as small as 15 nm in length.

Surface relaxation influences strain localization behavior.

Shear band formation is nearly size-independent, limited only by its own length scale.

Abstract

Molecular dynamics simulations indicate that surfaces strongly influence the strain localization behavior of amorphous nanowires in tension. A sample preparation routine that simulates casting was employed to facilitate the relaxation of the sample surface. Samples as short as 15 nm (7.5 nm in diameter) form dominant shear bands during deformation. The elastic energy release during plastic deformation is sufficient to provide the excess potential energy required for the shear band nucleation at rather small sample sizes. The results show that shear band formation is almost size-independent and is bounded only by its own length scale.