UNIVERSAL EQUATION OF STATE EMBEDDED ATOM MODEL

Atomistic simulations of defects in BCC metals were performed using LAMMPS code. With an embedded atom model potential (EAM) for calculations of atomic interactions. This potential is based on the Universal equation of state (UEOS) and is being developed in our group. With the aim of being suitable for a wide range of BCC metals.

The UEOS potential is fitted to individual elemental properties such as compression curves, elastic module, cohesive energy and equilibrium volume per atom.

In present work we tested the potential on a range of BCC metals including alkali- Na, K, Rb and Cs as well as transition metals - Va, Nb, Ta, Mo and W. The defect parameters calculated were formulation energy of six self-interstitial atoms (SIA) sites, vacancies, divacancies and vacancy migration energy. In addition the generalized stacking fault energy was calculated.

Very good agreement was found with ab initio calculation and, where available, for experimental quantities. In particular the UEOS-EAM potential predicts the dislocation core, which is in agreement with ab initio calculations, unlike many previous EAM models.