Effect of long-term aging on the fatigue crack growth rate of a nickel-based superalloy

▶ The coarsening of γ′ phase and carbides at grain boundaries and the precipitation of topologically close packed phases took place during long-term aging. ▶ The roughness induced closure effect was weakened by long-term aging. ▶ The interaction between dislocations and TCP phases, as well as coarsened γ′ phase, controls the fracture surface feature of the plastic zone ahead of crack tip.