Acta Phys. -Chim. Sin. ›› 2006, Vol. 22 ›› Issue (07): 771-776.doi: 10.3866/PKU.WHXB20060701

• ARTICLE •     Next Articles

Molecular Dynamics Simulation of the Structure Transformation before and after Ni Melting

HOU Huai-Yu;CHEN Guo-Liang;CHEN Guang   

  1. Department of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, P. R. China; State Key Laboratory for Advanced Metal & Materials, University of Science and Technology Beijing, Beijing 100083, P. R. China
  • Received:2005-11-03 Revised:2006-01-26 Published:2006-06-27
  • Contact: HOU Huai-Yu E-mail:hyhou@mail.njust.edu.cn

Abstract: A series of molecular dynamics simulations for the structure transformation during heating and melting of FCC Ni have been performed with the Tight-binding potential developed by Cleri and Rosato. The simulated melting point of Ni at constant pressure condition is between 1850 K and 1900 K. The static structural informations, such as the radial distribution functions and the distributions of the coordination numbers, have been obtained during the simulation. The calculated diffusion coefficient of the liquid Ni is about 5.02×10−9 m2•s−1 at 1900 K, which is consistent with the experimental result. The possible distortion of local structure of FCC crystal and the relevant changes of the types of the atom pairs (indexed by Honeycutt-Anderesen pair analysis technique) have been analyzed. The distributions of the short-range ordered (SRO) structures of FCC and defective icosahedra at different temperatures are calculated combining the local configuration search and H-A pair analysis methods. It is indicated that after melting a few SRO structures in FCC crystal are remained with distortion to a certain extent. A small quantity of the defective icosahedra in the liquid is also confirmed and their numbers are estimated. It suggested that the geometrical configurations of the local structure in liquid Ni are between the distorted cubooctahedron in FCC and the defective icosahedra.

Key words: Ni, Structure, Melting, Molecular dynamics simulation