Microstructure and microhardness evolutions of Cu47.5Zr47.5Al5 bulk metallic glass processed by rolling

Bulk Cu47.5Zr47.5Al5 metallic glass was rolled at different strain rates and temperatures. No phase transformation occurs in the as-rolled specimens except for shear bands. Free volume monotonously increases with increasing strain, and the rate of increase becomes larger with increasing strain rate or decreasing temperature. However, after an initial rise, the microhardness drops when the strain exceeds a critical value dependent on the rolling conditions. The increase in hardness is proved to result from the interaction of shear bands.