Determining the precipitation temperature of secondary γ’ phases by remelting method in Ni-based single crystal superalloys

Secondary γ′ phases are a typical structure in Ni-based single crystal superalloys. The unclear precipitation temperature makes it difficult to clarify how secondary γ′ phases affect properties at different temperatures. Especially, it is impossible to determine whether secondary γ′ phases precipitated during deformation or cooling after the high temperature deformation. Compared with the conventional two-step cooling method, the remelting method could better determine the precipitation temperature of secondary γ′ phases in Ni-based single crystal superalloys and confirm that they would likely be precipitated at 950 °C–1000 °C. Therefore, secondary γ′ phases could increase the yield strength of Ni-based single crystal superalloys at room temperature but don't affect that at 1100 °C due to the remelting of secondary γ′ phases.