Revealing the influential mechanism of strain ranges on cyclic-life saturation during creep-fatigue in Nickel-based superalloy DZ445

The creep-fatigue interaction has been recognized as the main failure mode of most structural components operating in high-temperature regime. cyclic life (Nf) usually decreases continuously with dwell time their interactions. However, Nf shows an abnormal change, i.e. keeps constant or slightly increases/decreases, present studied Nickel-based superalloy, DZ445. This means that generalized “Nf saturation” is achieved by a dynamic equilibrium between straight single superdislocations and dislocation networks corresponding to local homogeneous damage, respectively. saturation appears more easily increasing high strain ranges. variation mechanical response parameters, damage characterizations, phase involutions exhibits low amplitude under range. combined characteristics show easy occurrence range large deformations obtained local-damage. change rate deformation well confirmed above mechanism. parameters different criterion models cyclic-life “saturation phenomenon” unify mechanism soundly. work provides new theoretical basis guidance for safety design metallic materials establishment dislocation-based models.