Abstract: Nickel-based superalloy K403, a typical material for turbine blades, was stress aged to simulate blades used for a period of time, and then the previous stress aged specimens were subjected to recovery heat treatment. Microstructure and properties of the original specimen, the previous stress aged specimen and the recovery heat treated specimen were analyzed and tested by means of scanning electron microscope and mechanical testing machine, respectively. The results show that after recovery heat treatment, the strengthening phase γ′ in the microstructure is obviously refined in the K403 alloy test bar previous stress aged for different time, the morphology is close to cubic, and the high temperature tensile strength and rupture life of the recovered specimens are better than those of the untreated test bar. The longer the previous stress aging time, the higher the increase rate of high temperature rupture life of the alloy test bar after recovery heat treatment.

Key words: K403 nickel-based superalloy, recovery heat treatment, microstructure, properties