A many-body potential model which was based upon the second moment of the tight-binding approximation was used to simulate lattice defects. It was found that the chosen potential satisfactorily matched experimental data on cohesive energy, equilibrium lattice constants, vacancy formation energy and elastic constants (except C33). Mechanical and structural stability was satisfied, and the stacking-fault energy was found to be close to the lower edge of experimental estimates. The model was applied to mono-vacancy migration energies and the formation energy of single self-interstitials. It was found that there was a significant anisotropy of vacancy migration, and a low value of interstitial formation energy. These results were in accord with those of previous experimental and theoretical studies. The disadvantages of applying spherically symmetrical potentials to hexagonal close-packed metals whose c/a ratios were far from the ideal value were considered.

A.G.Mikhin, N.De Diego: Philosophical Magazine A, 1996, 73[4], 1211-22