Application of the embedded atom method to Ni3Al

Abstract

The embedded atom method [M. S. Daw and M. I. Baskes, Phys. Rev.B 29, 6443 (1984) used to calculate phase stability, lattice vibrational frequencies, point defect properties, antiphase boundary energies, and surface energies and relaxations for Ni₃Al. The empirical embedding functions and core-core repulsions used by this method are obtained. The equilibrium phases for the Ni-rich half of the composition range of Ni–Al are determined for 1000 K and compared with experiment. The elastic constants and vibrational modes of Ni₃Al are calculated and the elastic constants are compared with experiment. The formation energy, formation volume, and migration energies of vacancies are computed, and it is found that the formation energy of vacancies on the Ni sublattice is less than that on the Al sublattice. The (100) antiphase boundary is shown to be significantly lower in energy than the (111) antiphase boundary. The surface energies and atomic relaxations of the low index faces are computed, and it is shown that for the (100) and (110) faces that the preferred surface geometry corresponds to the bulk lattice with the mixed composition plane exposed.