High cycle fatigue life model of nickel-based single crystal superalloys based on critical plane approach

The high cycle fatigue life predication of the 〈001〉 orientation of nickel-based single crystal superalloys was studied by foreign scholars with critical plane approach based on octahedral slip system currently. However, without considering the characteristics of slip system parameters when the 〈111〉 orientation was loaded, the predication of high cycle fatigue life of the 〈111〉 orientation was inaccurate. Therefore hexahedral and octahedral slip systems was considered comprehensively when choosing the critical plane. Slid planes of maximum fatigue parameter could determine the position of critical plane, and the life models of the SSR(shear stress rang), CCB(Chu-Conle-Bonnen) and Walls were used for high cycle fatigue life prediction of single crystal superalloys. According to the results of high cycle fatigue test under 800℃ along 〈001〉, 〈011〉 and 〈111〉 orientations of DD6 nickel-based single crystal superalloys, the prediction accuracy of the life model was verified. The results indicate that the fitting coefficient of life model can reach to 0.9134 when the high cycle fatigue life of single crystal superalloys is predicted based on two slip systems.