Abstract
The kinetic glass transition of the Vit1 (Zr41.2Ti13.8Cu12.5Ni10.0Be22.5) bulk metallic glass (BMG) was calorimetrically studied by using the differential scanning calorimetry (DSC). A wide range of heating rate, q=0.5~100 K min-1, was adopted in the calorimetric experiments. The apparent values of the glass transition temperatures were determined from the DSC curves. Then the kinetic glass transition was analyzed by adopting the function in the form of the Vogel-Tammann-Fucher (VTF) type. In addition, by considering the glass transition of the BMG from non-equilibrium to kinetic equilibrium during the process of heating experiments, a new model which can be used to calculate the relaxation time near the glass transition temperature region was established. The relaxation time of the Vit1 BMG near the glass transition temperature region calculated by the new model was used to compare with the glass transition time (ttrans), as well as the relaxation time calculated by the viscosity and diffusion methods. The result shows that the relaxation time calculated based on the model can reflect the relaxation event reasonably near the glass transition temperature region. This work may provide some new perspectives or ideas for the study of the glass transition and relaxation of metallic glass.
Highlights
Glass transition during the solidification of liquid metal is attributed to the loss of the structural equilibrium in liquid
The preliminary objective of the differential scanning calorimetry (DSC) measurement is to determine the influence of the heating rate on the kinetic behavior of the glass transition
According to figure 1, it is concluded that the kinetic glass transition behavior of the bulk metallic glass (BMG) is strongly depended on the heating rate
Summary
Glass transition during the solidification of liquid metal is attributed to the loss of the structural equilibrium in liquid. In the past few decades, the dependence of the glass transition temperature on the heating rate of the reheating process or the cooling rate of the supercooled liquid has been investigated extensively for the glass forming alloy systems, and an obvious kinetic effect was observed. It is found that the α-relaxation time (τ) and the experimental time of the glass transition (ttrans) are roughly in the same order near the glass transition temperature (Tg) Based on this nature, the equations in the form of Vogel–Tammann–Fulcher (VTF) and Arrihenius types are often used to investigated the glass transition. The kinetic glass transition of a typical MG was investigated by using the differential scanning calorimetry (DSC) It was fitted by a function in the form of VTF type. Vit Bulk Metallic Glass by Calorimetric Method viscosity or diffusion measurement, were referred as well and used to compare with the present results
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