Abstract: Effect of solution treatment temperature (1080-1120 ℃) on the microstructure evolution, tensile properties and high temperature stress-ruptue properties of a new nickel-based superalloy were studied. The results show that with the increase of solution treatment temperature, the grain size of the tested superalloy increases, the number and size of the primary γ′ phase decrease, and the size and number of the secondary γ′ phase increase. When the solution treatment temperature exceeds 1095 ℃, the primary γ′ is almost re-dissolved and the grains grow rapidly. Moreover, the room temperature and 750 ℃ high temperature tensile strength and yield strength of the alloy decrease with the increase of solution treatment temperature, the endurance time increases and the creep plasticity decreases. The 1120 ℃+1080 ℃ double solution treatment cannot improve the room temperature and 750 ℃ high temperature tensile properties of the alloy, but can significantly improve the 750 ℃ creep properties. For the correlations among solution treatment temperature, microstructure, and mechanical properties, with the solution treatment temperature increases, the grain size of the alloy increases, the number of primary γ′ phases decreases, and the microstructure changes cause a decrease in the strength of the alloy and an increases in the endurance time.

Key words: nickel-based superalloy, solution treatment temperature, microstructure evolution, tensile properties, stress-ruptue properties