Microscopic Phase Field Study on the Site Preference of Al in Ni3V: Coordination Geometry Effect

Abstract

The site occupation behavior of Al in Ni3V phase with a DO22structure in Ni75AlxV25-xalloy was studied using the microscopic phase-field model which is based on the microscopic diffusion equations. Attribute to the coordination geometry effects, the concentration of Al are non-equal on the two non-equivalent Ni sites, and Al prefers to occupy the NiⅠsites. However, the Al does not prefer to occupy both of the two Ni sites, because the Al concentration on V site is intermediately between that on NiⅠand NiⅡsite. The calculated ordering energies suggest that the site preference of alloying elements are all energetic favorable.