The understanding of how pressure influences the rich phenomenology of glasses attracts
the scientific community not only from a theoretical point of view, but also for technological
applications. This is particularly true for metallic glasses (MGs), which exhibits suppression
of shear banding and inhibition of catastrophic mechanical failures under quasi-hydrostatic
compression, making deformed MGs appealing for technological applications [1].
Historically, the use of pressure as an experimental variable mainly concerned the
study of macroscopic quantities, owing in part to experimental convenience. Nowadays, our
understanding of the microscopic structural and dynamical effect of deformation in MGs
is limited to ex situ densified glasses. The recently developed 4th generation synchrotron
sources, like the ESRF synchrotron in France, made in situ pressure-dependent studies
experimentally achievable thanks to a 100 times higher coherent flux (up to 1012 photon/s).
This work investigates the atomic scale in situ pressure-dependence of a Au-based MG
by X-rays photon correlation spectroscopy (XPCS). From the structural point of view, pressure
is found to induce a reversible elastic densification of the system, while the dynamics
exhibits an hysteresis upon compression and decompression. Moreover, under hydrostatic
compression the atomic motion accelerates, as indicated by a decrease in the characteristic
relaxation time of the system, which suggests rejuvination. Our results support recently
developed theories predicting rejuvination of MGs under compression [2-3]. 

[1] J. Pan, Y.P. Ivanov, W.H. Zhou, Y. Li, A. L. Greer et al., Nature 578, 559-562 (2020).
[2] A. D. Phan, A. Zaccone, V. D. Lam, K. Wakabayashi et al., Phys. Rev. Lett. 126, 025502 (2021).
[3] N. K. Ngan, A. D. Phan, A. Zaccone et al., Physica Status Solidi (RRL) 15, 2100235 (2021).