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.