Abstract:In this paper, the effects of different heat treatment processes on the microstructure and properties of a new type of Ni-based superalloy ZGH451 were studied. The results show that the as-deposited microstructure is mainly composed of epitaxial micro-columnar grains, and there is γ/γ＇ eutectic exists among the interdendritic region. The segregation of element in the alloy results in the size difference of γ＇ phase between dendritic region and interdendritic region, which are 100 nm and 250 nm, respectively. The microstructure and properties of alloy with varying heat treatment processes are different: as the solution temperature increases from 1180 ℃ to 1350 ℃, the segregation degree of the alloy decreases gradually until the initial melting microstructure is found at 1350 ℃. With the first aging temperature increasing from 1050 ℃ to 1150 ℃, the size of γ＇ phase increases gradually, and its shape changes from spherical and other irregular shape to cube shape. In summary, the heat treatment process (HT2) suitable for the alloy is optimized. Compared with the as-deposited alloy, the grain size of alloy is significantly increased after the complete heat treatment, and the segregation and γ/γ＇ eutectic of the alloy are eliminated. The denser dislocation network is formed at the γ/γ＇ interface during tensile deformation at 1000 ℃. The tensile strength and yield strength are 520 MPa and 269 MPa, respectively, and the elongation is 11%.