Atomic-scale relaxation dynamics and aging in a metallic glass probed by X-ray photon correlation spectroscopy

TL;DR

This study employs X-ray photon correlation spectroscopy to explore atomic-scale relaxation and aging in a metallic glass, revealing a dynamical crossover and complex aging behaviors similar to soft glassy materials.

Contribution

It provides new insights into atomic-scale relaxation mechanisms and aging processes in metallic glasses, highlighting universal stress relaxation dynamics across different out-of-equilibrium systems.

Findings

Identification of a dynamical crossover between supercooled liquid and glassy states

Observation of multiple aging regimes with distinct dynamics

Analogies with soft glassy materials suggest universal relaxation mechanisms

Abstract

We use X-Ray Photon Correlation Spectroscopy to investigate the structural relaxation process in a metallic glass on the atomic length scale. We report evidence for a dynamical crossover between the supercooled liquid phase and the metastable glassy state, suggesting different origins of the relaxation process across the transition. Furthermore, using different cooling rates we observe a complex hierarchy of dynamic processes characterized by distinct aging regimes. Strong analogies with the aging dynamics of soft glassy materials, such as gels and concentrated colloidal suspensions, point at stress relaxation as a universal mechanism driving the relaxation dynamics of out-of-equilibrium systems.