Modeling of pseudotwinning in Fe₃Ga

Pseudotwinning is an important deformation mechanism that can produce reversible deformations similar to the shape memory phenomenon. Pseudotwinning merits further consideration from a modeling viewpoint as it could open new frontiers for discovery of alloys with recoverability of deformation. In this study, we focus on the Fe₃Ga (D0₃ and L1₂ lattices) with atomistic simulations. We present a pseudotwin nucleation model based on the generalized planar fault energy from first-principles calculations. The minimization of the total energy at the mesoscale associated with pseudotwin nucleation leads to determination of the twinning stress. The low energy barriers and twinning stress demonstrate that pseudotwinning in D0₃ Fe₃Ga is a possible deformation mode, but pseudotwinning is unlikely to occur in L1₂ Fe₃Ga due to the significantly high energy barrier and twinning stress. The predicted twinning stress is compared with experimental measurements, and the results show very good agreement. Hence, we suggest that the results provide a quantitative methodology to understanding and determining pseudotwinning in ordered alloys. (paper)