Influence of Ni addition on nanocrystallization kinetics of FeCo-based amorphous alloys

The effects of Ni addition on the crystallization temperature, apparent crystallization activation energy, nucleation and growth mechanism of melt-spun (Fe0.5Co0.5)73.5 − xNixSi13.5B9Nb3Cu (x = 0,2,4,5,8,10,15,20) alloys were investigated in this study. X-ray diffractometer (XRD) was used to analyze the microstructure, and differential scanning calorimeter (DSC) and the Johnson-Mehl-Avrami (JMA) model were applied to analyze and compare the results of the crystallization processes. The experimental results showed that the best thermal stability of samples and the maximum value of apparent activation energy were gained at 4 at.% addition of Ni. With increasing the Ni addition, thermal stability of residual amorphous matrix and resistance to secondary crystallization gradually decreased. During the secondary crystallization process, nucleation process continued until the end of crystallization, and there are interaction effects among the thermal stability of the residual amorphous phase, resistance to crystallization and variation in nucleation rate.