Site preference of ternary additions in Ni3Al

An electronic structure method is developed to examine the site preference of impurities in intermetallic compounds. The current method is based on a perturbation of the coherent potential medium, which represents the configurationally random alloy, within the tight-binding formulation of the linear muffin-tin orbital method. It is applied to predicting the site substitution behavior of a large set of impurities in Ni3Al (γ'). Impurities in this intermetallic compound may occupy exclusively the Ni or Al sublattices, or may exhibit no particular site preference. Although in a number of cases the experimental observations contradict each other, generally the predicted site preferences agree well with the available experimental data.