The nano-eutectic in the microstructure of semisolid Mg–6Zn–1Y alloy

Abstract The microstructures of Mg–6Zn–1Y (at%) alloys cooling in the 20 °C water and 20 °C air respectively from semisolid state at 540 °C were investigated in this work. An (α-Mg+I-phase) nano-eutectic was discovered in the water-cooled samples. The details of the nano-eutectic were investigated under TEM. Compared with the face-centered icosahedral I-phase solidified at slow cooling rate, the icosahedral type of I-phase solidified at fast cooling rate is primitive. The orientation relationship of the two phase in the nano-eutectic was also studied, namely { 01 1 1 } Mg ∥ { τ 10 } I − phase and { 10 1 0 } Mg ∥ 2 f I − phase . The two phases with different lattice structure matched as semi-coherent, which indicated that the interface was in a low energy state.