The effect of porosity size on the high cycle fatigue life of nickel-based single crystal superalloy at 980°C

Abstract The high-cycle fatigue (HCF) lives of nickel-based single crystal (N-SC) superalloys with different porosity sizes were investigated at 980 ° C . The test results show that the failure cracks are prone to initiate from large pores, and the oxide layer can also act as initiation site for secondary cracks when under low stress level. Despite the observation of oxide layer, the pore defect size remains the dominant parameter controlling fatigue life. Therefore, a prediction model based on the critical plane was used to quantitatively evaluate the effect of pure porosity size on the HCF property of N-SC superalloys. The prediction results show that the proposed model is effective and applicable in engineering.