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 potomial 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 12 111 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 s applied to calculate the core structure of the 1/2(111) screw dislocation and the critical resolved shear stress as a function of the angli, between the (211) slip plane and the maximum-stress plane. The results are in good agreement with previous first-principles calcula:ions and experimentally known mechanical behavior of body-centered cubic metals. (c) 2006 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.