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  • Depeng ZHOU, Dashan SUI, Jinyuan MA, Daxing GUI, Anping DONG, Baode SUN
    Accepted: 2024-01-29
    K439B nickel-based superalloy is a new type of alloy with a service temperature of up to 800 °C. However, there is a lack of in-depth research on the solidification crystallization characteristics of this alloy during the investment casting process. In order to explore the microstructure evolution characteristics of K439B nickel-based superalloy thin-wall castings, a thin-wall casting with wall thicknesses of 1 mm and 2 mm was designed, and gravity investment casting experiments and numerical simulations were conducted. Then, the microstructures of 1 mm and 2 mm thin-walls were comparative analysed. The experimental results demonstrated that the growth direction of dendrites in both 1 mm and 2 mm thin-walls was along the shell wall to the centre, but the difference was that the growth direction of dendrites in 1 mm thin-wall was closer to perpendicular to the angle of the shell wall. The average primary dendrite arm spacing (PDAS) was 60.64 μm for 1 mm thin-wall and 46.23 μm for 2 mm thin-wall, and the 1 mm thin-wall had a larger PDAS. Moreover, the average secondary dendrite arm spacing (SDAS) was 22.69 μm for 1 mm thin-wall and 19.31 μm for 2 mm thin-wall, and 1 mm thin-wall had smaller SDAS. The simulation results indicated that the 1 mm thin-wall had faster cooling rates and larger temperature gradients which were beneficial to refine grain sizes. These results could provide theoretical foundation to rationally design the casting process for the K439B nickel-based superalloy thin-wall casting.
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Founded in 1956 (monthly)

ISSN 1001-4381

CN 11-1800/TB

Sponsored by

AECC Beijing Institute of Aeronautical Materials

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