Thermo-Mechanical Fatigue Constitutive Model for Nickel-Based Single Crystal Superalloys

Based on the crystal plasticity theory, a thermo-mechanical fatigue constitutive model was proposed for nickel-based single crystal superalloys. By this model, thermo-mechanical fatigues for different crystal orientations were simulated. The results show that this method can simulate the thermo-mechanical fatigue of nickel-based single crystal superalloys very well. For in-phase thermo-mechanical fatigue, compression stress amplitude is greater than tension stress amplitude, and cyclic mean stress is negative. For out-phase thermo-mechanical fatigue, tension stress amplitude is greater than compression stress amplitude, and cyclic mean stress is positive. With the increase of cycles, material softens at high temperature semi-cycle, and hardens at low temperature semi-cycle. Crystal orientation influences thermo-mechanical fatigue property significantly.