Site preference of transition-metal elements in B2NiAl: A comprehensive study

First-principles supercell calculations based on density functional theory were performed to study the T = 0 K site preference of 3d (Ti-Cu), 4d (Zr-Ag) and 5d (Hf-Au) transition-metal elements in B2 NiAl. By adopting a statistical-mechanical Wagner-Schottky model within the canonical ensemble, the effects of finite temperature on site preference were further considered. The calculations showed that, at all alloy compositions and temperatures, Co, Tc, Ru, Rh, Re, Os, Ir and Pt have a consistent preference for the Ni sublattice, while Ti, Zr, Nb, Hf and Ta have a consistent preference for the Al sublattice. In contrast, the site preference of V, Cr, Mn, Fe, Cu, Mo, Pd, Ag, W and Au was found to depend on both composition and temperature. The present calculated results compare favorably with existing theoretical and experimental studies in the literature. (c) 2007 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.