2001 Volume 44 Issue 2 Pages 199-206
The present study investigated the relation between the interatomic potentials and thermal properties. Nineteen potential functions for tantalum, which was a high melting point material, were proposed based on the concept of FS potential with some modification on the functional forms, and their melting points and thermal expansion characteristics were investigated by using molecular dynamics simulations. The melting point was determined by starting NPT ensemble simulations with the initial configurations where the solid and liquid phases coexisted in a basic cell. The thermal expansion characteristic could be estimated without MD simulations by calculating the change in potential energy with isotropic expansions and compressions. The melting point was influenced by amplitude of thermal vibrations of atoms, and was decreased with decreasing of the modified elastic moduli. An empirical potential function for tantalum was derived, which satisfied some properties near 0 K, the lattice constant at 2500 K and the melting point.