Thermal behavior and glass transition of Zr-based bulk metallic glasses

The thermal behaviour of Zr-based bulk metallic glasses has been investigated in situ through the glass transition by means of differential scanning calorimetry, high temperature X-ray synchrotron diffraction, electrical resistivity, and dilatometry. The temperature dependence of the X-ray structure factor can be well described by the Debye theory. The Debye temperature of the glassy and the supercooled liquid state of Zr52Ti5Cu18Ni15Al10 is θ=412 and θ=162 K, respectively. The temperature coefficient of the electrical resistivity and the thermal expansion coefficient change also at the calorimetric glass transition temperature. The results point to a significant changes in the dynamics of molecular motion at Tg.