The effects of vacancies upon the phase diagram and order-disorder transition of a binary alloy were studied within the framework of ab initio statistical mechanics. It was shown that, for systems with structural vacancies, the phase diagrams were appreciably modified by vacancies; both qualitatively (with the appearance of new vacancy-ordered phases) and quantitatively (with a stabilization of phases over wider composition ranges, and decreases in transition temperatures).

Ab initio Statistical Mechanics for Alloy Phase Diagrams and Ordering Phenomena Including the Effect of Vacancies. F.Lechermann, M.Fähnle: Physical Review B, 2001, 63[1], 012104 (4pp)