Theory of pressure-induced rejuvenation and strain-hardening in metallic glasses

TL;DR

This paper presents a theoretical model explaining how high pressure causes metallic glasses to rejuvenate and harden through atomic dynamics and structural relaxation, aligning well with experimental observations.

Contribution

It introduces a theoretical framework linking pressure-induced structural changes to rejuvenation and strain-hardening in metallic glasses.

Findings

Pressure restricts atomic mobility and induces a higher-energy metastable state.

Rejuvenation under pressure is reversible.

The theory aligns with experimental results on metallic glasses.

Abstract

We theoretically investigate high-pressure effects on the atomic dynamics of metallic glasses. The theory predicts compression-induced rejuvenation and the resulting strain hardening that have been recently observed in metallic glasses. Structural relaxation under pressure is mainly governed by local cage dynamics. The external pressure restricts the dynamical constraints and slows down the atomic mobility. In addition, the compression induces a rejuvenated metastable state (local minimum) at a higher energy in the free energy landscape. Thus, compressed metallic glasses can rejuvenate and the corresponding relaxation is reversible. This behavior leads to strain hardening in mechanical deformation experiments. Theoretical predictions agree well with experiments.