Study of the aging and rejuvenation heat treatment of superalloy GTD111

ABSTRACT The nickel-based superalloy GTD111 is commonly used in the manufacture of gas turbines blades, for applications in power generation and aeronautics. The present study investigates this superalloys’s behavior “as provided” from the manufacturer and previously heat treated for γ’ size reduction and morphology changing from spheroidal to cuboid. The samples were aged in laboratory and then submitted to the rejuvenation heat treatment with the objective of recovering the degraded microstructure. For each condition, microhardness, γ’ size and percentage were evaluated using scanning electron microscopy. For the aging stage a study of γ’ coarsening rate measured from experimental results and the calculated rate from γ’ coarsening theory is presented. Two equations that describe the γ’ coarsening kinetics of this study are presented and compared with equations from others authors that studied the same superalloy. The results showed that samples previously heat treated (rejuvenated) have lower coarsening rate when compared to the initial state provided from the blade casting process.