Atomic modelling of Co, Cr, Fe, antisite atoms and vacancies in B2–NiAl

The formation and preference site energies and volume changes of single defects and pairs of defects of ternary alloying elements in NiAl intermetallic compound were studied by the density functional theory. Exceptionally, a small formation energy of Co defect in Ni sublattice was found. The Co, Cr, Fe atoms and vacancies prefer to reside in the Ni sublattice. The formation energy for Co–Co nearest neighbor pair is the smallest. The Ni antisite in Al sublattice requires less energy than the Al antisite in Ni sublattice.