First-principles investigation of the site preference and alloying effect of Mo, Ta and platinum group metals in γ′-Co3(Al, W)

The alloying effect of Mo, Ta and platinum group metals on the properties of gamma'-Co-3(Al, W) are studied using supercell models. It is demonstrated that Mo, Ta, Rh Ir and Pt can stabilize the gamma' phase, and three types of site preference are recognized. The binding energy and the lattice constant of the gamma' phase is modified and the distinct alloying effect of those elements is further revealed by investigating the impurity-induced charge density and the partial density of states. (C) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.