Angle Annular Dark Field-scanning Electron Research Articles

Regulating kinetics of deformation-induced phase transformation in amorphous alloy composite via tuning nano-scale compositional heterogeneity in crystalline phase

Nano-scale compositional heterogeneity of crystalline phase in Ti-based amorphous alloy composites (AACs) has been successfully tuned by tuning cooling rate in solidification process. And the effect of compositional heterogeneity on the kinetics of the deformation-induced phase transformation was investigated by in-situ synchrotron-based high-energy X-ray diffraction (HE-XRD) and ex-situ transmission electron microscopy. In-situ HEXRD experiments provide obvious evidence that with the decrease of the cooling rate during solidification, the critical stress of the deformation-induced phase transformation becomes lower, and the phase transformation rate becomes higher. Further high angle annular dark field-scanning electron microscopy investigation shows that the occurrence of the nano-scale Zr-lean compositional heterogeneity, which can favor the nucleation of the martensite, is the reason for the variation of the phase transformation kinetics.