In situ TEM observation of the glass-to-liquid transition of metallic glass in Fe–Zr–B–Cu alloy

The glass-to-liquid transition was evaluated by in situ transmission electron microscope observation of crystalline Cu globule aggregation in Fe–Zr–B amorphous or supercooled liquid matrices in Fe50Zr10B20Cu20 melt-spun ribbon. Globule aggregation was not observed near the critical glass transition temperature, but was observed near the glass transition temperature evaluated by conventional differential scanning calorimetry measurements. The viscosity of Fe–Zr–B-based metallic glass may decrease during the glass-to-liquid transition, and a polygonal crystalline phase may form by Cu globule aggregation.