Crystallization kinetics of Cu38Zr46Ag8Al8 bulk metallic glass in different heating conditions

Abstract

The crystallization kinetics of Cu38Zr46Ag8Al8 bulk metallic glass in non-isothermal mode and isothermal mode are investigated by differential scanning calorimetry. In non-isothermal conditions, the average value of activation energy is determined by Kissinger equation, and the value is around 310kJ/mol. The crystallization enthalpy is about 28.69J/g. In addition, the local Avrami exponent is adopted to describe the crystallization process. In isothermal route, the average value of activation energy for crystallization is calculated by the Arrhenius equation, and the value is about 451kJ/mol. The crystallization enthalpy is about 1.63J/g. And the Avrami exponent n ranges from 4.10 to 4.74, which indicates that the crystallization mechanism is mainly governed by constant nucleation rate. The created phases in the two conditions are different which can be confirmed by the X-ray diffraction test, this result is in accordance with the different crystallization enthalpies, but it's different with other investigations.