Crack-tip stress–strain fields in single crystal nickel-base superalloys at high temperature under cyclic loading

This work is related to life prediction of high-pressure single crystal turbine blades. Stress and strain fields are first analysed at the tip of a static crack subjected to creep-fatigue loading, assuming an elasto-viscoplastic single crystal behaviour model. Local ratchetting effects are observed, depending on the distance from the crack-tip. Creep-fatigue loadings are compared with pure fatigue and pure creep loadings. The significant differences are pointed out, especially stress relaxation and amount of plastic slip. These results will be useful for the development of a new life prediction tool, based on local approach to fracture.