Mechanical properties of Cu46Zr46Al8 metallic glasses affected by liquid-liquid phase transition

The increasing utilization of metallic glass (MG) has resulted in a heightened requirement for precise regulation of its liquid. Liquid-liquid phase transition (LLPT) is often observed in glass-forming liquids, and its influence on mechanical properties of glasses necessitate further elucidation. In this work, we discover that the elastic modulus of MGs quenched below LLPT temperature increases by 12 % compared to MGs quenched above LLPT temperature, and the number of activated shear bands during deformation increases by 40 %. Through transmission electron microscopy and molecular dynamics simulation, we find that CuZr2 nanocrystals with good plasticity are formed in the low-temperature MGs, which facilitates the generation of numerous shear bands during deformation, thereby enhancing the plasticity of the sample. Conversely, brittle AlCu nanocrystals are formed in the high-temperature MGs, which hampers the initiation of shear bands and leads to the formation of localized stress concentration. This study not only advances the comprehension of solidification process involved in MGs preparation, but also offers insight into modulating mechanical properties of MGs from liquid states.