Title: The formation of quasiregular microstructure in highly undercooled Ni70.2Si29.8 eutectic alloy
Abstract: High undercooling (about 392 K) was achieved in bulk eutectic Ni70.2Si29.8 alloy melt using glass fluxing combined with cyclic superheating. Surprisingly, the microstructure of eutectic Ni70.2Si29.8 transits from irregular to quasiregular when the undercooling exceeds 340 K. The morphology transition at large undercooling is analyzed based on the solution entropy of eutectic phases. The forming process of quasiregular microstructure is ascribed to a transition from faceted-faceted to nonfaceted-nonfaceted eutectic concurring with increased undercooling.