Failure mechanism of single-crystal superalloy NiAlReRu components with film cooling holes under the coupling high-speed rotating and high temperature condition

Abstract

In order to make up for the deficiency that the laboratory testing of standard samples cannot approximately simulate the turbine blade geometry and service environment, the creep experiment of the nickel-based single crystal superalloy NiAlReRu components with film cooling holes (FCHs) is carried out under the coupling high-speed rotating and high temperature condition. The component with the FCHs exposed to the coupling high-speed rotating of 20000 rpm and high temperature of 1000 ℃ continuously lasts 255.92 h until it breaks. The microstructural evolution and fracture process are analyzed. The results indicate that the existence of the FCHs evidently changes the stress distribution of the region with the FCHs, which makes the microstructural evolution of γ′ phase significantly different. The component is fractured along the second row of the FCHs and the normal direction of the fracture surface is basically parallel to the centrifugal force direction. The fracture process can be divided into three typical stages. The coupling effect of temperature and stress on the failure mechanism is discussed.