Cyclic deformation behavior of a nickel-base superalloy under fatigue loading

• The fatigue property of the alloy was analyzed.
• The prediction of fatigue life was proposed.
• The effects of strain amplitudes on cycle deformation behavior were analyzed.
• The low cycle fatigue mechanism was discussed.
• The nature of cycle deformation behaviors during fatigue process was discussed.

Total strain-controlled low cycle fatigue (LCF) tests of a nickel-base superalloy were performed at 650 °C. Combined with fatigue test data, cyclic deformation behaviors of the alloy were analyzed. Fatigue cycle life decreases significantly with the increasing total strain amplitude. The cyclic hardening and cyclic softening phenomena occur during the LCF process, which are associated with the total strain amplitude. Fracture morphologies and dislocation characteristics were observed through scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The combined effects of brittle fracture and ductile fracture are the main LCF fracture mechanism of the alloy.