Isokinetic and isoconversional study of crystallization kinetics of a Zr-based metallic glass

Abstract

The crystallization kinetics of Zr_69.5Cu₁₂Ni₁₁Al_7.5 metallic glass is studied under non-isothermal condition using differential scanning calorimetry (DSC). The kinetic parameters, viz. the activation energy (E) and the Avrami exponent (n), for the primary (first) crystallization peak are obtained using the isokinetic and the isoconversional methods. The so-obtained E and n are utilized to derive theoretical normalized heat flow curves through the Kolmogorov-Johnson-Mehl-Avrami (KJMA) equation. The comparison of the experimental and theoretical normalized heat flow curves at different heating rates demonstrates that the completely isokinetic description of the crystallization process is not suitable. On the other hand, the isoconversional methods in combination with the KJMA equation provide better understanding of the kinetics of the crystallization process.