Structural evolution of a CuZr-based bulk metallic glass composite during cryogenic treatment observed by in-situ high-energy X-ray diffraction

•The cooling induced structural evolution of CuZr-based BMGC is in-situ studied.•The hydrostatic pressure exerts a crucial role on the martensitic transformation of B2 CuZr phase.•The thermodynamics mechanism of the phase transformation of CuZr phase is clarified. [Display omitted] In-situ high-energy X-ray diffraction and molecular dynamic simulation were employed to study the structural evolution of a B2 phase reinforced CuZr-based bulk metallic glass composite in different structural states during cryogenic treatment between 300 K and 100 K. No phase transformation occurs in the as-cast sample during cryogenic treatment, while the pre-strained sample undergoes martensitic transformation and reverse martensitic transformation. The ambient temperature, uniaxial stress, and hydrostatic pressure on the B2 CuZr phase are closely related to the phase transformation behavior of the CuZr phase in the pre-strained composite sample. Molecular dynamic simulation confirms the experimental results. The findings in this work will help to clarify the mechanism of the martensitic transformation in the B2 CuZr phase, and finely tune the structure and mechanical behaviors of CuZr-based bulk metallic glass composites.