The effects of
heat treatment on the microstructural and tensile properties of conventionally cast M963 superalloy both at
ambient
temperature and 900℃ have been investigated. The results show that the solution treatment at 1 210℃ for 4h followed by air cooling causes an increase in the tensile strength but a decrease in ductility especially at high temperatures; After the solution treatment, aging at 850℃ for 16h followed by furnace cooling further increases the tensile strength and the ductility at high temperature but decreases the ambient temperature ductility. Scanning electron microscope (SEM) observation reveals that the primary MC carbide becomes different and secondary M6C carbide precipitates at grain boundaries and interdendritic regions during the solution treatment at 1 210℃ for 4h. Fine g phase particles precipitate from the g solid solution during air-cooling following the solution treatment. The aging treatment at 850℃ for 16h makes a fine g phase precipitate and grow. Analysis of the fracture surface indicates that the fracture mechanism varies with
heat treatment condition. The effects of heat treatment on the tensile properties at both ambient and high temperatures is discussed in terms of interaction between dislocations and particles.