# Atomic‐Level Structural Characteristics of β‐Relaxation in Metallic Glasses

## TL;DR

This study reveals how β-relaxation in metallic glasses is linked to specific atomic structures and motions, offering new insights into their mechanical properties.

## Contribution

The paper experimentally characterizes β-relaxation at the atomic level and links it to specific structural features and dynamic behaviors.

## Key findings

- β-relaxation is associated with tricapped trigonal prism-like atomic structures and fast atomic motions.
- Cyclic heating shows β-relaxation is irreversible but can be reactivated through high-temperature rejuvenation.
- The study provides a new pathway for understanding structural-dynamic correlations in metallic glasses.

## Abstract

The β‐relaxation is one of the crucial relaxation modes in glasses, which significantly influences their mechanical properties, structural heterogeneity, and glass transition. However, due to detection limitations, the β‐relaxation has not been fully characterized and understood. In this work, in situ synchrotron radiation X‐ray diffraction and absorption techniques are utilized to track the β‐relaxation during heating and find that it can be reflected in the evolution of cluster structures within the first shells of metallic glasses. Through molecular dynamics simulations, it is further demonstrated that the β‐relaxation is also well consistent with fast atomic motions linked with specific Voronoi polyhedra and chemical constitutions characterized by more excess free volume. The cyclic heating experiments provide evidence for the “irreversible” β‐relaxation, which involves an event that is decayed during the sub‐T
g annealing; however, it can be reactivated by subsequent high temperature rejuvenation. The discovery paves a new pathway for the study of β‐relaxation, unveiling the origin of β‐relaxation based on experimental and theoretical structural analysis methods.

Using in situ synchrotron radiation X‐ray techniques, this study experimentally characterizes β‐relaxation at the atomic scale, linking it explicitly to tricapped trigonal prism (TTP)‐like atomic structures and fast atomic motions. Cyclic heating reveals β‐relaxation as irreversible yet reactivatable through rejuvenation, offering unprecedented insight into structural‐dynamic correlations essential for understanding metallic glasses’ macroscopic behaviors.