Unveiling the Asymmetry in Density within the Shear Bands of Metallic Glasses

TL;DR

This paper presents a new model explaining the asymmetry in density variations within shear bands of metallic glasses, combining topological charges and a dipolar field to match experimental observations.

Contribution

The authors introduce a novel topological charge-based model that accurately describes density asymmetries in shear bands of metallic glasses.

Findings

Model captures local densification and dilation imbalance

Analytical solution aligns with experimental data

Potential to explain broader shear band phenomena

Abstract

Plastic deformation in metallic glasses at room temperature leads to the development of shear bands due to shear localization. In many experiments, shear bands have shown local density variations along their path, with a distinct imbalance in magnitude between local densification and dilation. However, a comprehensive mechanistic understanding or theory to explain this asymmetry has been lacking until now. Here, we introduce a new model that consists of a sequential arrangement of alternating topological 'charges', generating a dipolar field. The resulting microscopic displacement field, when integrated into the deformation gradient tensor, provides an accurate analytical solution for the observed imbalances in the density variations. The implications of this method are discussed, highlighting the potential to elucidate a broader range of observations in shear bands.