Development of the interatomic potentials for W-Ta system

Abstract

Tungsten (W) and W-based alloys are regarded as the most promising candidates for plasma facing materials (PFMs) in future fusion reactors. In this work, new interatomic potentials for Ta element and W-Ta alloy have been developed based on the Finnis-Sinclair formalism, in combination with our previously developed potential for W. The potential parameters for Ta were determined by fitting to a set of experimental and first-principles data, including lattice constant, cohesive energy, elastic constants, point defects formation energies and Rose’s equation of state for the bcc lattice. The W-Ta cross parameters were fitted to the first-principles data of the formation energies and binding energies of Ta atom with different point defects in bulk W. The present potentials not only reproduce some important physical properties of various point defects, but also predict the non-degenerate/compact core structure of the 1/2 〈1 1 1〉 screw dislocation in bulk Ta, which is the same as DFT calculations. The developed potentials were expected to be suitable for atomistic simulations of point defects evolution in Ta and W-Ta binary alloys.