Energetics of additive site selection and consequences for alloy stability

Abstract

Understanding additive site selection is important for elucidating and improving the changes in behavior of intermetallic compounds through alloying. We have performed supercell total-energy calculations giving the energy preference for site selection of additivities to \ensuremath{\gamma}-TiAl. For V, Cr, and Mn the Ti site is preferred, but with a substantial decrease of energy in going from V to Mn, while for B the Al site is preferred by a slightly larger energy than that preferring the Ti site for V. Thus, the site-selection energy preference for the substituted species ``follows the Periodic Table'' in expected behavior. This difference in site-selection energy probably plays an important role in the stability and behavior of the alloy.