Single Activation Enthalpy of Diffusion in a ZrTiCuNiBe Bulk Glass around the Glass Transition after Structural Relaxation

摘要

B and Fe diffusion coefficients measured at and below 553 K in the Zr_(46.8)Ti_(8.2)Cu_(7.5)Ni_(10)Be_(27.5) bulk glass after long time relaxation at 553 K are significantly lower than before relaxation. They agree with diffusion coefficients obtained from the extrapolated high temperature (> 600 K) Arrhenius behavior of diffusion indicating that after proper relaxation the diffusion follows a uniform temperature dependence over the entire temperature range around the glass transition. Measurements of the enthalpy recovery of this bulk glass around the calorimetric glass transition indicate reversible structural changes with a relaxation time of about 10~6 s at 553 K.