Characterization of nanoscale mechanical heterogeneity in a metallic glass by dynamic force microscopy

TL;DR

This study uses dynamic force microscopy to reveal nano-scale mechanical heterogeneity in metallic glass, measuring local viscoelastic variations and correlation lengths that align with shear transformation zones, bridging atomic models and macroscopic behavior.

Contribution

First experimental observation of nano-scale mechanical heterogeneity in metallic glass using dynamic force microscopy.

Findings

Measured ~12% energy dissipation variation

Correlation length of heterogeneity ~2.5 nm

Heterogeneity aligns with shear transformation zones

Abstract

We report nano-scale mechanical heterogeneity of a metallic glass characterized by dynamic atomic force microscopy. Apparent energy dissipation with the variation of ~12%, originating from non-uniform distribution of local viscoelasticity, was characterized. The correlation length of heterogeneous viscoelasticity was measured to be ~2.5{\pm}0.3 nm, which is well consistent with the dimension of shear transformation zones for plastic flow. This study provides the first experimental observation on the nano-scale mechanical heterogeneity in a metallic glass, and may fill the gap between atomic models and the macroscopic properties of metallic glasses.