Polymorphic Transformation and Magnetic Properties of Rapidly Solidified FeCoNiSiB High-Entropy Alloys.

In this work, the microstructural evolution and magnetic performance of the melt-spun amorphous and amorphous-crystalline FeCoNiSiB high-entropy alloys (HEAs) during crystallization were investigated, respectively. Upon heating fully amorphous ribbons, a metastable BCC supersaturated solid solution together with a little NiSi crystals first precipitated and then the (Fe,Co)₂B crystals formed until the full crystallization was achieved. With further increasing temperature after full crystallization, a polymorphic transformation from a metastable BCC phase to two types of FCC solid solutions occurred.