Energetic Analysis of Deformation Twins in Titanium Alloys by First-principles

Deformation modes in hcp α-titanium are energetically analyzed by using first-principles calculations. For the prismatic and basal slip, the generalized stacking fault energy curves are calculated. While a quasi-stable state existed at the center of the prismatic slip path in the Al-doped case as well as pure titanium, the local minimum disappeared for the substitutional doping of Cu. For the {1012} and {1122} deformation twinnings, the twin boundary energy is evaluated. In the case of the {1122} twin boundary, the mirror glide structure is more stable than the mirror reflection structure.