A tight-binding atomistic approach for point defects and surfaces applied to the o-Al[formula omitted]Co[formula omitted] quasicrystalline approximant

Abstract

We implemented an N-body potential for the Al–Co interactions and applied it to the o-Al13Co4 quasicrystalline approximant. We show its ability to model this complex compound in the presence of point and extended defects (atomic vacancies and surfaces). The importance of stress relaxation in vacancy formation is highlighted through the mapping of local pressures in the bulk compound. Thanks to the many body character of the potential, the surfaces could be investigated which was not done before in atomistic studies of this complex phase. Our classical simulations point up the competition between preserving the cohesion by minimizing the number of broken bonds and avoiding the presence of Co atoms at the surface. This study opens the way to large scale simulations of phenomena involving complex metallic alloys in particular at their surfaces.