Angular-dependent interatomic potential for tantalum

A new angular-dependent semi-empirical interatomic potential suitable for atomistic simulations of plastic deformation, fracture and related processes in body-centered cubic Ta has been constructed by fitting to experimental properties and a first-principles database generated in this work. The potential reasonably reproduces a variety of properties of Ta, including elastic constants, thermal expansion, high-pressure behavior, the vacancy formation and migration energies, surface energies, gamma surfaces on the {1 1 0} and {2 1 1} planes, energy along the twinning and anti-twinning deformation paths, structure of the {2 1 1} twin boundary and energies of alternate crystal structures of Ta. The potential is applied to calculate the core structure of the 1/2 〈1 1 1〉 screw dislocation and the critical resolved shear stress as a function of the angle between the {2 1 1} slip plane and the maximum-stress plane. The results are in good agreement with previous first-principles calculations and experimentally known mechanical behavior of body-centered cubic metals.