Microstructure evolution of Zr65Al7.5Cu12.5Ni10Ag5 bulk metallic glass due to rolling and its influence on the thermal stability

X-ray diffraction (XRD), differential scanning calorimetry (DSC) and high-resolution transmission electron microscopy (HRTEM) are employed to investigate the microstructure evolution of Zr65Al7.5Cu12.5Ni10Ag5 bulk metallic glass subjected to rolling at room temperature. The strain rates are controlled to be 10(-4)-10(-3) s(-1). The results show that the plastic deformation during rolling behaves as an inhomogeneous mode with the characteristic of shear bands, which results in the two-state characteristic of atomic movement from competition between the ordering and disordering processes. The icosahedron-like clusters precipitate in the transition regions between the shear bands and the amorphous matrix, and they tend to aggregate into nano-sized orders. The results of DSC indicate that the onset precipitation temperature of I-phase during heating of the metallic glass obviously decreases due to rolling. However, the time window for the completion of amorphous-to-icosahedral phase transformation is evidently lengthened. The microstructure evolution during rolling and its influence on the thermal stability are discussed. (C) 2011 Elsevier B.V. All rights reserved.