Structural essence of abnormal crystallization behaviors during the annealing of Cu₃₃Zr₆₇ metallic glass

During the non-isothermal annealing of Cu₃₃Zr₆₇ metallic glass (MG), two abnormal crystallization behaviors were detected. Nano-crystal growth ceasing leads to amorphous/nano-crystalline dual-phase structure, and residual amorphous crystallization is accompanied by grain coarsening. The structural evolutions of Cu₃₃Zr₆₇ MG at atomic-level were observed by high-resolution transmission electron microscopy. By analyzing structural factors, the nano-crystal growth ceasing is attributed to the spatially variation of icosahedral short-range order density arising from the structural heterogeneity of Cu₃₃Zr₆₇ MG, and the concurrence of crystallization and grain coarsening is due to higher thermal stability of residual amorphous as compared to bct-CuZr₂ nano-structure.