Microstructural evolution and restoration of creep property for a damaged K403 alloy after rejuvenation heat treatments

Rejuvenation heat treatments can restore the microstructures and mechanical properties of the degraded turbine blades in gas turbine engines.Herein we analyze the effects of rejuvenation heat treatments on the microstructural characteristics and mechanical properties of damaged and undamaged specimens of a Ni-based superalloy,K403.The damaged specimens were found to have degraded microstructures and shorter creep lifetime than the undamaged specimen.The rejuvenation heat treatment proved beneficial,especially for specimens exposed to damage for 50 h.In addition,the microstructure recovery and creep life were found to depend on the predamage durations of the specimens.A y’-precipitate-based creep lifetime model was established to predict the residual lifetime based on the microstructural information.