Understanding the relation between creep-fatigue fracture mechanisms and intergranular dislocation accommodation of a high chromium steel using nanoindentation characterization

•The creep-fatigue fracture mechanism of P92 steel was studied by nanoindentation.•Longer cyclic life of P92 steel under CF loading with shorter dwells.•The fracture mechanism shifts from fatigue to CF damage with increasing dwell time.•A normalized damage indicator is proposed to characterize the fracture mechanism.