Thermodynamics-based method considering orientation and notch effect to predict the high cycle fatigue life of a nickel-based single crystal superalloy

The high cycle fatigue (HCF) life of DD6 at 760 ℃ was studied by performing a large number of experiments. A new thermodynamics-based life prediction method was proposed by considering the thermodynamic entropy change during the fatigue process. The model is not only suitable for smooth specimens but also can be applied to the life evaluation of notched specimens and those with different orientations. Finally, the life of an aeroengine blade with different orientations was qualitatively evaluated by the proposed model, which demonstrated that the model can be used to analyze the influence of crystal-axis deflection angle on blade life.