Point-defect and stacking-fault properties in body-centred-cubic metals withn-body interatomic potentials

The properties of vacancies, self-interstitial atoms and translation stacking faults have been studied by computer simulation using the n-body empirical potentials recently developed for the body-centred-cubic transition metals by Finnis and Sinclair. Vacancy formation energy, formation volume and migration energy have been computed and the results are compared with other theoretical and known experimental values. Formation energy and volume have been calculated for six possible interstitial configurations and, although the expected 〈110〉 dumbbell is most stable in Mo and α-Fe, the 〈111〉 crowdion is favoured in Ta, Cr and W. The energetics of interstitial migration have been studied in detail for Mo, and the migration steps which lead to two-dimensional diffusion do not have the lowest migration energy. The n-body potentials predict the absence of stable translation stacking faults on the {110} and {112} planes.