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 δ, the activation energies for sub-T_g and α-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 α-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 α-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.