Nanocrystallization mechanism of amorphous Fe78B13Si9

The nanocrystallization mechanism of an amorphous alloy is discussed based on the kinetics of open nanospaces in Fe78B13Si9. There already exists a high concentration of Fe-enriched fluctuated sites with open nanospaces in the amorphous matrix. The structural and compositional fluctuation helps transient short-range Fe diffusion in the metastable amorphous matrix with an increase of temperature, triggering highly concentrated α-Fe nucleation. Along with the growth of α-Fe nucleus, Fe atoms are transferred from the intergranular amorphous phase to Fe-based nanocrystallites. The nanocrystallization of α-Fe is achieved through nucleation by short-range Fe diffusion and its growth by nanovoid-mediated long-range Fe diffusion.