Site preference of transition-metal elements in L10-TiAl: A first-principles study

Abstract

The site preference of 3d (Ti-Cu), 4d (Zr-Ag) and 5d (Hf-Au) transition-metal elements in L10 TiAl is studied using a combination of first-principles supercell calculations and the statistical mechanical Wagner-Schottky model. Our key finding is that both temperature and alloy stoichiometry can strongly affect the site occupancy behavior of ternary alloying elements in L10 TiAl. We further predict that the tendency of transition metals to occupy the Al sites in TiAl increases with increasing d-electron number along a series.