Quasicrystalline effects on the mechanical relaxation behavior of a Ti45Zr16Ni9Cu10Be20 metallic glass

In order to investigate the effects of quasicrystalline phase on the mechanical relaxation behavior of a metallic glass, dynamic mechanical properties of as-spun and heat treated Ti45Zr16Ni9Cu10Be20 ribbons were measured. From the temperature dependence of the shift factor, obtained by the master curve of tan delta, the activation energies for sub-T-g and alpha-relaxation of both ribbons were calculated and their relaxation mechanisms were investigated. The activation energy for sub-T-g relaxation of heat treated ribbon which contains the quasicrystalline phase in the amorphous matrix showed higher value than that of the as-spun amorphous ribbon, while the activation energy for alpha-relaxation of both ribbons showed similar value. The activation energy for the sub-T-g relaxation of the heat treated ribbon was even higher than that for the alpha-relaxation of it. The high value of the activation energy for the sub-T-g relaxation of a heat treated ribbon can be said to be ascribed to the highly cooperative motions associated with the phason-type atomic rearrangement of the quasicrystalline phase embedded in the amorphous matrix of the heat treated Ti45Zr16Ni9Cu10Be20 ribbon. (C) 2009 Elsevier B.V. All rights reserved.