Chemically induced structural heterogeneities and their relationship with component dynamics in a binary metallic liquid

摘要

We performed ab initio molecular dynamic simulations and evidenced a clear connection between chemical short-range order (CSRO) and dynamic properties in the liquid and undercooled Al_(93)Cr_7 alloy. In the liquid phase, we find that the interplay between CSRO and icosahedral short-range order leads to a strong decoupling of component diffusion. Upon cooling, this interplay induces the development of an icosahedral-based medium range order referring to Cr atoms which can be correlated to the occurrence of dynamic heterogeneities (DHs) characterized by AI fast-dynamics regions and Cr-rich slow-dynamics regions. All these results yield a possible scenario of the structural origin of DHs in a metallic liquid which presents a decoupling of component diffusion.