Fatigue life prediction model based on critical plane of nickel-based single crystal superalloy

A model was developed for fatigue life prediction of nickel-based single crystal superalloy based on critical plane and cyclic damage accumulation. The slip plane with the maximum inelastic strain energy density was chosen as the critical plane of nickel-based single crystal superalloy which was subjected to the most serious damage. Based on the results of viscoplastic deformation analysis on slip systems, the relation between the fatigue life and the parameters of the critical plane such as the maximum resolved shear stress, the maximum shear strain rate due to slip, shear strain range due to slip, strain ratio and the tension/compression dwell frequency, was formulated. The life prediction method was validated with the fatigue testing results of DD6 at 760°C. The experiments agree well with the calculations, and almost all of the results fall in the scatter band of 2.