ALCHEMI study of site distributions of 3d-transition metals in B2-ordered iron aluminides

Abstract

ALCHEMI has been used to determine the site distributions of the 3d-transition metals Me = {Ti, V, Cr, Mn, Co, Ni, Cu} in B2-ordered iron aluminides of stoichiometry Fe 50Al 45Me 5. These alloying additions exhibited an increasing ‘Fe’-site preference with increasing atomic number. Elements Co, Ni and Cu were found to occupy the ‘Fe’ site exclusively, displacing 10% of the Fe host element to the ‘Al’ anti-site. None of the alloying elements exhibited an exclusive ‘Al’-site preference. The element Ti exhibited the largest ‘Al’-site occupancy, with ∼85% of the alloying element occupying the ‘Al’ site. The residual ‘Fe’-site occupancy (15%) can be attributed to the kinetics of the site-equilibration mechanism.