Linking the pressure dependence of the structure and thermal stability to α- and β-relaxations in metallic glasses
- Jie Shen
- Antoine Cornet
- Alberto Ronca
- Eloi Pineda
- Fan Yang
- Jean-Luc Garden
- Gael Moiroux
- Gavin Vaughan
- Marco Di Michiel
- Gaston Garbarino
- Fabian Westermeier
- Celine Goujon
- Murielle Legendre
- Jiliang Liu
- Daniele Cangialosi
- Beatrice Ruta
2025-10-03
Glasses derive their functional properties from complex relaxation dynamics that remain enigmatic under extreme conditions. Although the temperature dependence of these relaxation processes is well established, their behavior under high-pressure conditions remains poorly understood due to substantial experimental difficulties. In this study, we use cutting-edge experimental techniques to probe the pressure evolution of the relaxation spectrum in a Zr 46.8 Ti 8.2 Cu 7.5 Ni 10 Be 27.5 metallic glass across gigapascal pressure ranges. Our findings reveal two distinct relaxation mechanisms under high pressure: In the β-relaxation regime, compression drives the system with reduced atomic mobility and enhanced structural disorder, without appreciable density changes. Conversely, α-relaxation under pressure promotes density-driven structural ordering that improves thermal stability. Notably, the transition between these regimes occurs at a constant T / T g,P ratio, independent of applied pressure. These results provide crucial insights for decoupling the competing structural and relaxation contributions to glass stability, establishing a systematic framework for tailoring glass properties through controlled thermomechanical processing.