The dynamical shear deformation-induced HCP → FCC process in Ti3Al was systematically investigated using both molecular dynamics and ab initio methods. The details of the dislocation initiation, the microstructure evolution and the velocity field effect were presented. The molecular dynamics simulation revealed that, with the increment of the velocity field, the deformation-induced dislocation slide could happen by three modes based upon the nucleation of an initial FCC core, i.e. the continued fault slipping could initiate every other three layers, every other one and then three layers and every other one atomic layer. The corresponding transformed structure was an alternate existence of the single FCC and HCP plate, 18R fault, and the FCC plate containing three ABC units or more. The mechanism was further explored based upon ab initio calculations of the detailed energy variation at different fault transition modes. The results promoted systematic understanding of the stress-induced fault transition mechanism in experimental observations.

Shear Deformation in Ti3Al - Atomic, Dynamic And Static Simulations. Y.L.Liu, L.Zhang, S.Q.Wang, H.Q.Ye: Modelling and Simulation in Materials Science and Engineering, 2008, 16[8], 085008 (13pp)