The low-cycle fatigue behavior and an entropy-based life prediction model for Nickel-based single crystal superalloy across an extensive temperature range

Nickel-based single-crystal superalloys (Ni-SX) are prominently utilized in the fabrication of turbine blade materials for advanced aero-engines, owing to their commendable material characteristics. This paper delves into the low cycle fatigue (LCF) characteristics of a second-generation Nickel-based single-crystal superalloy across a temperature spectrum ranging from room temperature to 1000 °C. During this procedure, there is an escalation in the trend towards deformation homogenization, leading to a transition in fracture mode from shear fracture to normal fracture. A novel approach is introduced in the form of an entropy-based fatigue life prediction model, grounded in the correlation between cumulative plastic strain and entropy increase rate. Through a comparative examination with experimental data, the model demonstrates proficiency in precisely forecasting the fatigue life of Ni-SX under diverse strain amplitudes and temperature conditions.