Nucleation-and-growth process in Fe80B20amorphous alloys

A nucleation-and-growth process in Fe80B20 amorphous alloy ribbons has been studied using differential scanning calorimetry using an isothermal analysis mode. Measurements have been performed in the temperature range between the glass transition and the onset of crystallization. Experimental data have been fitted using the theoretical Johnson-Mehl-Avrami equation. Kinetic parameters as well as the activation energy of crystallization have been determinated. It is shown that the mechanism, which governs the nucleation-and-growth process is independent of annealing temperature; while the nucleation frequency and growth rate are dependent on temperature value. Finally it is shown that the whole devitrification of the samples cannot be completely described using only the nucleation-and-growth process.