Influence of nearest neighbor atoms and coordination polyhedron on atomic volume of sigma phases

Abstract

We calculated the atomic volume with respect to the atomic charge of the constituent atoms in the complete set of ordered configurations for several binary sigma systems by using first-principles calculations. The calculation results indicate that both the nearest neighbor (NN) atoms and coordination polyhedron (CP) affect the atomic volume of sigma phases. For a specific atom on a specific site, the more negative the atomic charge, the larger the atomic volume; the more the NN large atoms and the higher the CP symmetry, the larger the space to accommodate the specific atom, thus the larger the atomic volume.