Crystallization in Zr60Al15Ni25 bulk metallic glass subjected to rolling at room temperature

The microstructure evolution of Zr60Al15Ni25 bulk metallic glass during rolling at room temperature is investigated by differential scanning calorimetry (DSC), high-resolution transmission electron microscopy (HRTEM) and selected area electronic diffraction (SAED). The HRTEM images show that shear bands are produced in the rolled specimens, indicating the essence of inhomogeneous deformation due to rolling, and that there exist nanocrystals with size of about 5-10 nm in the transition regions between the shear bands and the undeformed matrix in the rolled specimens with deformation degrees of 80% and 95%. Based on the polyhedral structure model and the shear transformation zone (STZ) theory, the influence of viscous flow, free volume, viscosity and the stress situation on the crystallization behaviors in the metallic glass during rolling is discussed.