Relaxation and crystallization of Zr41.2Ti13.8Cu12.5Ni10Be22.5 bulk amorphous alloys

The influences of relaxation on glass transition and on the crystallization behavior of Zr41.2Ti13.8Cu12.5Ni10Be22.5 bulk amorphous alloys were investigated. The alloys were annealed at 643 K, which was below the glass transition temperature, for different annealing times to investigate the effects of structural relaxation. The thermal properties, precipitated phases and microhardness of the annealed samples were studied with differential scanning calorimetry (DSC), X-ray diffraction (XRD) and Vickers microhardness test respectively. In situ annealing in a heating stage in a transmission electron microscope was performed and the microstructure was studied. With increasing annealing time, the step change in the DSC curve around the glass transition region was broadened and the crystallization temperature decreased. The main crystalline phases were found to be Zr2Cu, Be2Zr and some other unidentified phases. The hardness of the annealed samples increased with increasing annealing time.