First-principles study on the site preference of Dy in B2 NiAl

The site preference behavior of Dy in B2 NiAl was investigated by a combination of the first-principles and statistical-mechanical Wagner-Schottky method. At T = 0 K, the site occupation of Dy in B2 NiAl is highly stoichiometric-dependent, whereas, Dy showing a consistent preference for the Al sublattices in three types of B2 NiAl at temperatures higher than 300 K. The density of states (DOS) and Mulliken bond population calculations show that the interactions between Al (s, p) electrons and Ni (d) electrons are much stronger in the Dy-doped NiAl than those in pure NiAl, which could be responsible for the improvement of mechanical properties of the Dy-doped NiAl.