| Abstract Scope |
Due to the very low stacking fault energy, FCC HEA can readily be transformed into HCP. Such a transformation can also occur with an intermediate BCC phase. In this work, we conduct atomistic simulation on phase transformations in equiatomic-ratio HEA during deformation and analyze the mechanisms for these transformations. Our simulation results reveal a sequential phase transformation from FCC to a transitory BCC phase, and finally to an HCP phase. Lattice transformations are carefully analyzed based on the simulation results. We find that, during FCC → BCC transformation, the orientation relationships satisfy the well-known Kurdjumov-Sachs (K-S), Nishiyama-Wasserman (N-W), and Pitch orientation relationships, and the lattice correspondence is exactly the Bain mechanism. We also find that the BCC → HCP transformation is achieved purely by atomic shuffling in the {110}BCC planes, resulting in the formation of two HCP variants. These new HCP variants exhibit a natural {10-12} twin relationship. |