The order evolution in amorphous Fe78Si9B13 ribbon during annealing process

The amorphous Fe78Si9B13 ribbons were annealed at various temperatures below the crystallization temperature (Tx). The order evolution in the amorphous Fe78Si9B13 ribbon and its effect on the ductile-brittle transition during annealing process were studied using XRD and SEM methods. It is shown that the ordered structures of Fe3Si and FeSi appear at the temperature of 200-300 °C with the life from 15 min to 15 h. During low temperature relaxation (LTR), the life of the ordered ferrous compounds is longer than during high temperature relaxation (HTR). Moreover, the life of Fe3Si is longer than FeSi during LTR, while it is much shorter than FeSi during HTR. The formation time of the further ordered FeSi is very close to the critical time of the ductile-brittle transition of amorphous Fe78Si9B13 ribbon, which suggests that the formation of further ordered FeSi results in the embrittlement of the ribbon.