The energies of stacking-fault teirahedra in f.c.c. metals

Total energies for intermediate truncated stacking-fault tetrahedra are calculated. The effect of local stress fields on the stability of the tetrahedra is considered. The results are presented in a form that can be applied to any f.c.c. metal. These results do not agree with previous treatments of the same problem. Stacking-fault energies can be estimated from the calculations. Application to the results of Loretto et al. (1965) leads to the prediction of γ=17±4 ergs/cm2 for silver, γ=55±11 ergs/cm2 for gold and γ=73±15 ergs/cm2 for copper.