Formation of τ-phase in Fe60Nb10B30 amorphous alloy with a large supercooled liquid region

A metastable nanocrystalline tau-phase with a complex fcc structure was confirmed as a primary precipitation phase in the melt-spun Fe60Nb10B30 amorphous alloy with a two-stage crystallization process. The phase transformation from the amorphous phase to the tau-phase takes place at 1001 K at a heating rate of 0.67 K/s.The microstructure of this phase is composed of homogeneously distributed fine grains in the diameter range below 10 nm. The composition of this phase is almost the same as that of the starting amorphous phase. The tau-phase decomposes into alpha-Fe, Fe3B and Fe2B phases in the second-stage reaction.