Simulation for Nucleation of Metals by Molecular Dynamic Method.

通过分子动力学方法模拟金属成核。

• 批准号: 04650622
• 负责人: OHSASA Kenichi
• 金额: $ 1.41万
• 依托单位: Hokkaido University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1992
• 资助国家: 日本
• 起止时间: 1992 至 1993
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-04650622/
• 关键词: Simulation; Nucleation; Molecular dymanic method; Iron; Solidification; Radial distribution function; 均質核生成; 異質核生成

A molecular dynamic method to simulate the nucleation process in liquid iron was investigated. The results obtained are summarized as follows.1)The basic simulation program of molecular dynamic procedure was developed based on cubic cell with periodic boundary condition. This program is written in FORTRAN and works on a personal computer, workstation and also on a super computer. The behavior of iron atoms during simulation can be displayd with 3d wire frame model.2)The form of interatomic potential of iron near the melting point was determined by simulating melting process of iron, and the calculated radial distribution function of liquid iron at 2000K agreed with experimentally measured one.3)The simulation of nucleation process in undercooled liquid iron was carried out. Liquid iron was quenched from 2000K to the temperature rejion with undercooling of 300-400K, and then maintained for 50000 steps which corresponds to 435ps. Results are shown as follows.a)The rise in temperature due to latent heat evolution with crystallization was observed.b)It was recognized that the critical undercooling required for the nucleation is about 350 K, and this fact agrees with the reported value of critical undercooling for homogeneous nucleation in liquid iron.c)It was observed that the crystallization rate in liquid iron increases with increasing the degree of undercooling.

研究了一种分子动力学方法来模拟铁液中的成核过程。所得结果总结如下：1)基于具有周期边界条件的立方胞，开发了分子动力学过程的基本模拟程序。该程序是用FORTRAN编写的，可以在个人计算机、工作站和超级计算机上运行。铁原子在模拟过程中的行为可以用三维线框模型来显示。2)通过模拟铁的熔化过程，确定了铁在熔点附近的原子间势形式，计算得到的铁液在2000K时的径向分布函数与实验测得的一致。3)对过冷铁液的成核过程进行了模拟。将铁液从2000K淬火至过冷300-400K，然后保持50000步，对应435ps。结果如下所示。a)观察到结晶过程中潜热演化引起的温度升高。b)认识到成核所需的临界过冷约为350 K，这一事实与报道的铁液均匀成核的临界过冷值一致。c)观察到铁液的结晶速率随着过冷程度的增加而增加。