- Ab initio calculations are performed to study the site preference occupation for the transition metals additive in FeAl (B2) and their influence on the thermodynamic stability of this phase. It was found that alloying by Ni results in significant stabilization of the phase. Alloying by V slightly stabilizes and alloying by Cr slightly destabilizes the structure. Our calculations predict that V prefers to occupy Al position in defectless FeAl, Ni occupies Fe position, and Cr shows slight preference to occupy the position of Al. When the vacancy on the Fe site is formed in the vicinity of alloying transition metals, V and Ni atoms remain on the same sites as in perfect FeAl, while Cr changes to its preferable site.