Generalized stacking-fault energies, for the (111) and (100) planes of stoichiometric material, were calculated within the framework of density functional theory by using the local-density approximation and the full-potential linearized augmented plane-wave method. The most striking result was a mechanical instability of the (111) antiphase boundary with respect to shear along <112> towards the complex stacking fault. The energy of the (111) antiphase boundary was therefore larger than the energy of the complex stacking fault. This, in turn, had about twice the energy of the super-intrinsic stacking fault.

Generalized Stacking-Fault Energies for TiAl: Mechanical Instability of the (111) Antiphase Boundary J.Ehmann, M.Fähnle: Philosophical Magazine A, 1998, 77[3], 701-14