Effect of Notch Radius on the Thermal Fatigue Property of a New Guide Vane Materials

Thermal fatigue property of a directionally solidified nickel-base superalloy with different notch radius was studied. The results show that cycle numbers of crack initiation increase and resistance of thermal fatigue decreases with the rise of notch radius at the upper temperature of 1050°C. Thermal fatigue crack initiates at carbide or oxidized cavity. The join of oxidized cavity makes crack propagate. The propagation rate lowers with the increasing notch radius. Crack propagation direction is along <110> direction in {111} plane. The stress concentration drops and thermal fatigue property improves with the increase of notched radius.