The effects of notch size and material microstructure on the notch sensitivity factor for notched components

Nickel base superalloys are used in hot sections of gas turbine engines due to its high strength and good creep, fatigue, and corrosion resistance at high temperature. In this paper, a new probabilistic approach based on weakest-link theory that accounts for the effects of the microstructure, notch size and notch acuity is described and applied to nickel base superalloy to determine the fatigue notch factor, notch sensitivity index and the probability of forming microstructurally small crack from the notch root. The simulation results obtained from this framework are compared with experimental results and results obtained using existing classical methods for notched polycrystalline nickel base superalloys for the different notch root radii and acuities considered.