Simulation for Nucleation of Metals by Molecular Dynamic Method.

1993 Fiscal Year Final Research Report Summary

• Project/Area Number: 04650622
• Research Category: Grant-in-Aid for General Scientific Research (C)
• Allocation Type: Single-year Grants
• Research Field: 金属加工(含鋳造)
• Research Institution: Hokkaido University
• Principal Investigator: OHSASA Kenichi Hokkaido Univ., Fac.of Eng., Associate Professor, 工学部, 助教授 (90111153)
• Project Period (FY): 1992 – 1993
• Keywords: Simulation / Nucleation / Molecular dymanic method / Iron / Solidification / Radial distribution function

Research Abstract

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.