Energetics and electronic properties of vacancies, anti-sites, and atomic defects (B, C, and N) in B2-FeAl alloys

Atomistic modeling based on density functional theory within the framework of the generalized gradient approximation is used to show the trends in the energetics and the electronic properties of single, double, and triple-like defects in B2-FeAl alloy, without phase transformation. A systematic study of vacancy, boron, carbon, and nitrogen substituting Fe or Al atoms in a supercell structure consisting of 16-atoms is presented. The changes of structural properties and lattice parameters due to the addition of defects in the FeAl matrix are compared, and the site preference of each type of defects is determined from the total energy calculations. Also, the trends in densities of states and valence charge profiles are presented and discussed together with the bond mechanism (ionicity and covalency).