Abstract: Precipitation-strengthened solution treated GH4096 superalloy was cooled by five different cooling methods. Standard size turbine disc baffles under five cooling rates were prepared separately. The specimens were subjected to high temperature creep tests at 700 ℃ and 690 MPa, and the performance of the five GH4096 superalloy disc baffles was compared. By introducing a novel in-situ statistical characterization method, the in-situ observation and statistical quantitative distribution observation of the strengthening phase in the alloy material-primary, secondary, and tertiary γ′ phases were realized across scales in the form of images. The changes of γ′ phase morphology and size distribution in the materials before and after high temperature creep were compared and discussed. The results show that the GH4096 superalloys obtained by the five cooling rates all exhibit good high-temperature creep properties. The γ′ phase distribution density of the materials under the five processes is 210-260 μm^-2. After the high temperature creep test, the number of γ′ phases is significantly reduced, and the γ′ phase distribution density drops to 150-200 μm^-2. Among them, the decrease of γ′ phase density is mainly due to the decrease of γ′ phases with a diameter less than 36 nm.

Key words: superalloy, cooling rate, γ′ precipitates, high temperature creep, quantitative statistical characterization