纯铁液凝固过程的分子动力学模拟

摘要

Solidification processes of liquid Fe was investigated by the molecular dynamics simulation with the long-range Finnis-Sinclair (F-S) potential which combines the N-body potential with a van der Waals tail. The solidification process of iron atoms is a series of process from disorder to short-range order and then long-range order, the structure of short-range order should be clusters of iron atoms;the total energy of the system of the solidification process reduce gradually, the freezing point of perfect crystal of iron is about 2 400 K, all of which is confirmed by Radial Distribution Function (RDF), Mean Square Displacement (MSD) and the fig-ure of condensed state of iron atoms.%为了研究纯铁熔液体系在凝固过程中的演变行为，采用分子动力学方法和带有范德瓦尔斯项的长程F-S势函数对液态Fe凝固过程的结构和能量演变进行模拟。径向分布函数、原子均方位移函数和Fe原子的聚集状态变化图像显示，凝固过程是Fe原子由无序向短程有序再向长程有序的变化过程，其中的短程有序结构可能是Fe原子组成的团簇结构；凝固过程中体系的总能量变化呈逐渐降低，Fe单质完美晶体的凝固温度约为2400 K。