Plasticity-induced structural anisotropy of silica glass

TL;DR

This study demonstrates that mechanical shear can induce permanent structural anisotropy in silica glass, evidenced by molecular dynamics simulations showing orientational order without significant microstructural change.

Contribution

It reveals that shear plastic flow can create lasting anisotropic structures in silica glass, expanding understanding of amorphous material behavior under mechanical stress.

Findings

Shear induces permanent anisotropy in silica glass.

Anisotropy is detectable via fabric tensor analysis.

Microstructure remains largely unchanged.

Abstract

Amorphous silica density at ambient pressure is known to depend on thermal history (through the quenching rate) but also, at room temperature, on the maximum pressure applied in the past. Here we show that beyond density, a mechanical loading can endow the structure with an orientational order. Molecular dynamics simulations show evidence that amorphous silica develops a permanent anisotropic structure after extended shear plastic flow. This anisotropy which survives for an unstressed specimen is revealed markedly by the fabric tensor computed over the Si-O-Si orientations, albeit the SiO4 tetrahedra microstructure remains mostly unaltered.