Nano-Ductility in Silicate Glasses is Driven by Topological Heterogeneity

TL;DR

This study demonstrates that nanoscale ductility in silicate glasses is driven by topological heterogeneity, with localized flexible regions enabling plastic deformation and non-brittle fracture modes, as shown through molecular dynamics simulations.

Contribution

It reveals that nanoscale heterogeneity in atomic network rigidity causes nano-ductility in silicate glasses, a novel insight into their fracture behavior.

Findings

Localized floppy modes enable plastic deformation.

Heterogeneous plastic events percolate to cause non-brittle fracture.

Nano-ductility is intrinsic to multi-component silicate glasses.

Abstract

The existence of nanoscale ductility during the fracture of silicate glasses remains controversial. Here, based on molecular dynamics simulations coupled with topological constraint theory, we show that nano-ductility arises from the spatial heterogeneity of the atomic network's rigidity. Specifically, we report that localized floppy modes of deformation in under-constrained regions of the glass enable plastic deformations of the network, resulting in permanent change in bond configurations. Ultimately, these heterogeneous plastic events percolate, thereby resulting in a non-brittle mode of fracture. This suggests that nano-ductility is intrinsic to multi-component silicate glasses having nanoscale heterogeneities.