The formation of full lamellar structures from Ni-25Â at% Si melts

Directional solidification experiments have been performed on Ni-25 at% Si alloy using electron beam floating zone method. The Ni-25 at % Si hypereutectic alloy can form a fully regular eutectic microstructures consisting of γ-Ni31Si12 and Ni, with thin β1-Ni3Si layers and star-like β1-Ni3Si existing at the boundary and in the Ni-rich lamellas, respectively. The results indicate that there is full lamellar αNi-γ (Ni31Si12) eutectic structures at the nominal composition of Ni3Si which can be develop as in situ composite with improved toughness at the nominal composition of Ni3Si.