Structural topological signature of high-temperature non-Arrhenius crossover in metallic glass-forming liquids
NN Ren and LN Hu and B Wang and KK Song and PF Guan, SCRIPTA MATERIALIA, 200, 113926 (2021).
The Arrhenius to non-Arrhenius crossover of the structural relaxation dynamics, happened at T-A when cooling the metallic melts, has been widely studied, but the underlying structural evolution is still an open issue. Through molecular dynamics (MD) simulations combined with the topological order analysis of atomic structure, we investigated the evolution of the hidden structural topological features associated with the non-Arrhenius crossover. It was found that the average spatial connectivity degree k of the characteristic slow atoms approaches 3 at T-A in various metallic glass-forming liquids (MGFLs), corresponding to the constant dynamic heterogeneity. The non-Arrhenius behavior below T-A is attributed to the cooperative motions of atoms with k > 3 by developing a stable topological network. Our findings shed light on the structural origin of the relaxation dynamics in MGFLs. (C) 2021 Published by Elsevier Ltd on behalf of Acta Materialia Inc.
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