ALCHEMI STUDY OF SITE DISTRIBUTIONS OF 3D-TRANSITION METALS IN B2-ORDERED IRON ALUMINIDES

ALCHEMI has been used to determine the site distributions of the 3d-tr ansition metals Me = {Ti, V, Cr, Mn, Co, Ni, Cu} in B2-ordered iron al uminides of stoichiometry Fe50Al45Me5. These alloying additions exhibi ted 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 similar to 85% of the alloying element occupying the 'Al' site. The residual 'Fe '-site occupancy (15%) can be attributed to the kinetics of the site-e quilibration mechanism. (C) 1997 Acta Metallurgica Inc.