Self-diffusion in Zr_(55)Al_(10)Ni_(10)Cu_(25) and Pd_(40)Cu_(30)Ni_(10)P_(20) Bulk Metallic Glass

摘要

Self-diffusion coefficients of Ni in Zr_(55)Al_(10)Ni_(10)Cu_(25) and of Ni and Pd bulk metallic glass below and above the glass transition temperature T_g have been measured with an ion-beam sputter-sectioning technique using the radioactive isotope ~(63)Ni and ~(103)Pd. The diffusion coefficients in the supercooled liquid region are much higher than those extrapolated from low temperature data in the amorphous region. The temperature dependence of the diffusion coefficients exhibits non-Arrhenius behaviour in the supercooled liquid phase. Such a deviation from the Arrhenius plots is interpreted by a cooperation of moving tracer atom with the surrounding atoms. The difference of the diffusion behaviour in between Zr-Al-Ni-Cu and Pd-Cu-Ni-P glasses is attributed to the different structural stability of both glasses.