Understanding <i>T</i>_A from dynamic heterogeneity in metallic glass-forming liquids

How to generally describe the structural relaxation upon cooling is still mysterious for metallic glass-forming liquids with various dynamic fragilities. Here a scaling collapse of the temperature dependence of structural relaxation time, τ_α(T), is achieved by introducing the characteristic temperature T^*(α_2,max) and characteristic time scale τ^*(α_2,max) with any identical dynamic heterogeneity α_2,max in 12 metallic glass-forming liquids, which is consistent with our previous reports[1]. The scaled master curve τ_α/τ^*(α_2,max) ~ T^*(α_2,max)/T experiencing a crossover behavior from Arrhenius to non-Arrhenius implies that T_A is one of T^*(α_2,max). It is further confirmed by the almost constant α_2,max(T_A) for all the systems studied here and achieving a general description of relaxation time, together with τ_A (the structural relaxation time at T_A). Our findings provide a new insight of T_A from the perspective of dynamic heterogeneity and shed light on the glass forming of metallic liquids.

References
[1] L. J. Wang, N. Xu, W. H. Wang and P. F. Guan, Phys. Rev. Lett. 120, 125502 (2018).