Tuning β Relaxation via the Glass-To-Glass Transition in a Pseudo-High Entropy Metallic Glass

The transformation from one amorphous phase to another is known as the glass-to-glass transition, which induces significant changes in the structure and properties of metallic glasses. However, the influence of this transition on the β relaxation behavior remains to be clarified. Here, based on classical molecular dynamics simulations of the Zr₆₅Al₇Fe₇Co₇Ni₇Ag₇ pseudo-high entropy alloy, we find that the as-cast sample (g_A) undergoes a glass-to-glass transition upon heating at around 849 K. After isothermal annealing at 900 K, g_A transforms into a new metallic glass (g_B), and g_B does not undergo a glass-to-glass transition upon heating. Compared to g_A, g_B exhibits a higher probability of Al-Al and Al-Ag bonding and a lower probability of bonding between Al and other atoms. Furthermore, g_B also exhibits a more pronounced β relaxation peak and a higher characteristic temperature of β relaxation (T_β) on the E″/E″_max - T/T_α curve. By comparing the atomic mobility in g_A and g_B at their respective T_β, we further demonstrate that g_B contains a larger number of fast-moving atoms. This higher mobility makes a significant contribution to the more pronounced β relaxation peak observed in g_B. Our findings provide a fresh perspective for utilizing the glass-to-glass transition to tune the β relaxation in metallic glasses.