Microstructure evolution and mechanical properties of Cu₄₆Zr₄₇Al₇ bulk metallic glass composite containing CuZr crystallizing phases

Cu₄₆Zr₄₇Al₇ ternary bulk metallic glass (BMG) and its composite containing CuZr crystallizing phases were obtained through water-cooled copper mold casting. There is an obvious microstructure transition of CuZr crystallizing phase due to the decrease in the cooling rate: disperse small dendrites-regular radial dendrites-martensite phase. Under compression, the CuZr crystallizing phases particularly for martensite phase yield first and stimulate the formation of multiple shear bands in the matrix, which enhanced the ductility of the composite. The quasi-static compression fracture surface of the BMG its composites display a mixture of three distinct patterns: vein-like, smooth regions and river-like patterns. The river-like pattern was related with the secondary shear bands or tertiary shear bands and its area fraction on the fracture surface was dependent on the plasticity.