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 {110} and {211} planes, energy along the twinning and anti-twinning deformation paths, structure of the {211} twin boundary and energies of alternate crystal structures of Ta. The potential is applied to calculate the core structure of the 1/2 Æ111æ screw dislocation and the critical resolved shear stress as a function of the angle between the {211} 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. 2006 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.