CRYSTALLIZATION OF STABLE AND METASTABLE EUTECTICS IN FESIB METALLIC GLASSES

Two iron-based metallic glasses, Fe78Si9B13 and Fe78Si10B12, have been examined after isothermal annealing at different temperatures and it has been found that both stable and metastable eutectics can crystallize simultaneously during the annealing process. At low temperatures, the majority of the eutectic cells in the structure consist of α-iron and the stable Fe2B phase with a lesser amount of the α-iron and metastable Fe3B eutectic, whereas at higher temperatures the metastable eutectic predominates. It is suggested that these observations may be explained in terms of the presence of overlapping coupled zones of both the stable and metastable eutectics in the phase diagram. © 1990 Chapman and Hall Ltd.