Polytetrahedral short-range order and crystallization stability in supercooled Cu64.5Zr35.5 metallic liquid

Abstract

Development of reliable interatomic potentials is crucial for theoretical studies of the relationship between chemical composition, structure and observable properties in glass-forming metallic alloys. Due to the ambiguity of potential parametrization procedure, certain crucial properties of the system, such as stability against crystallization or symmetry of the ground state crystal phase, may not be correctly reproduced in computer simulations. Here we address this issue for Cu64.5Zr35.5 alloy described by two modifications of embedded atom model potential, as well as by ab initio molecular dynamics. We observe that, at low supercooling, both models provide very similar liquid structure, which agrees satisfactory with that obtained by ab initio simulations. Hoverer, deeply supercooled liquids demonstrate essentially different local structure and thus different stability against crystallization. The system demonstrating more pronounced icosahedral short-range order is more stable against crystallization, which is in agreement with Frank's hypothesis. © 2019 Elsevier B.V.