Study on fatigue and constitutive model of superalloy blade by <i>in situ</i> sampling

Purpose Due to the complexity and harshness of the gas turbine operating environment, turbine blades, a key component of the gas turbine, face a variety of challenges, including high temperatures, high speeds and corrosive environments, which are exacerbated by stress concentrations caused by geometric discontinuities in the blades. Design/methodology/approach Two small notched specimens with the same stress concentration coefficient but different geometry were designed. Through the high-temperature fatigue test, the effect of geometric structure on the fatigue performance of small notched specimens was compared. The life law and failure mechanism of the two types of notched specimens are clarified, and the test results are simulated by a viscoplastic constitutive model with coupled damage and the simulation results are consistent with the cracking position in the test and the cumulative damage value proposed in this paper can reflect the life relationship of the two notched specimens. Findings National Natural Science Foundation of China (12302102). Originality/value In this paper, the fatigue properties of in situ sampling of nickel-based superalloy MAR-M247 blades (small notched samples) were studied.