Crystallization behavior and kinetics of Cu-Zr-Al-Be bulk metallic glass

Abstract

The crystallization kinetics of the Cu43Zr43M7Be7 bulk metallic glass were studied by differential scanning calorimetry(DSC) in the continuous heating and isothermal annealing modes. Only one major peak could be detected on the DSC traces Of Cu43Zr43Al7Be7 bulk amorphous alloy, and the activation energy for crystallization corresponding to the peak determined by the Kissinger method was resulted of 239 kJ/mol. The isothermal kinetic, analyzed by the Johnson-Mehl-Avrami equation yielded values for the Avrami exponents in the range 1.69 to 2.37, which implied a crystallization governed by a three-dimensioned growth. Primary phases were essentially the cubic structure CuZr together with the Cu10Zr7 phase. At higher temperature, the CuZr disappeared while the Cu10Zr7 became predominant. After long term annealing at 731 K, the phases were Cu10Zr7, Cu2ZrAl and Al3Zr5.