NUCLEATION AND GROWTH-KINETICS OF STABLE AND METASTABLE EUTECTICS IN FESIB METALLIC GLASSES

Two iron-based metallic glasses, Fe78Si10B12 and Fe72Si10B18, have been examined in detail after partial crystallization at a series of temperatures. The number and size of the eutectic cells-of both stable and metastable eutectics-have been determined as functions of time and temperature and the results compared with theoretical nucleation models. It has been found that the extent to which quenched-in nuclei from the original planar flow casting operation influence the subsequent crystallization behaviour depends on alloy composition and on the annealing temperature. The results indicate that it is possible to control the type, number and size of the crystallization products in the microstructure by suitable choice of annealing conditions.