Zr53Cu18.7Ni12Al16.3过冷熔体的原子结构以及动力学性质的研究

本文采用第一性原理分子动力学方法,模拟了Zr53Cu18.7Ni12Al16.3过冷液体的原子结构,以及其对动力学性质的影响.通过对Al原子周围的偏对分布函数的分析,发现该过冷液体的原子结构可用以Al原子为中心的团簇来表征.这种局域结构稳定程度的空间不均匀性,导致了过冷液体的动力学在空间分布上的不均匀性,即出现速度较慢的原子.这种慢原子的出现,使得该过冷液体在过冷相区内发生动力学迟缓,从而抑制了晶化.

Structure and dynamics of Zr53Cu18.7Ni12Al16.3 supercooled liquid studied by computer simulation

In this work,ab initio molecular dynamics simulation has been implemented to study the atomic structure and dynamics of Zr53Cu18.7Ni12Al16.3 supercooled liquid.Through analyzing the partial pair distribution functions of Al,it has been found that the atomic structure of this liquid could be represented by the Al-centered clusters.These clusters consist of stable Kasper polyhedra and unstable polyhedra which can be regarded as distorted ones.Due to this spatially heterogeneous stability of local structure,the supercooled liquid shows heterogeneous distribution of dynamics in space,that is,some atoms move slower.This kind of slow atoms causes the dynamical slowing down,and inhibits the nucleation in the supercooled liquids.