About this Abstract |
| Meeting |
11th International Symposium on Superalloy 718 and Derivatives 2026: Legacy, Innovations, and Future Directions
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| Symposium
|
Superalloy 718 and Derivatives 2026: Legacy, Innovations, and Future Directions
|
| Presentation Title |
Cooling Rate Sensitivity of Disk Superalloys for the Next Turbine Generation |
| Author(s) |
Angela Quadfasel, Thomas Witulski, Manuel Köbrich |
| On-Site Speaker (Planned) |
Angela Quadfasel |
| Abstract Scope |
Mechanical properties of next generation γ’ superalloys, like creep sensitivity or strength, depend on the distribution of secondary and tertiary γ’-size and phase fractions, which evolve during cooling after solution annealing and heat treatment. Especially for turbine disks with large cross sections, the cooling rate sensitivity of those materials is a relevant feature in contrast to Inconel 718. For materials with high cooling rate sensitivity the maximum cross section is limited, due to the loss of strength in the centre of the part for moderate cooling rates. Unfortunately, the increasing of cooling rate results in residual stresses, which influences the further processing and the properties in use.
In this work the cooling rate sensitivity of the aerospace relevant alloys Udimet720 Li and Rene 65 is compared. While alloying composition of both alloys are relatively close to each other, the microstructure evolution during classical forging and annealing process is different. Both alloys were cooled down after solution annealing with different cooling rates, representative for the centre of a large disk.
Only for very high cooling rates the size of secondary γ’ is similar for Udimet 720 and Rene 65. With decreasing cooling rate the γ’ size is increasing for both alloys but more pronounced for Udimet 720. Therefore, Udimet 720 shows higher cooling rate sensitivity than Rene 65. This is also visible in the evolution of yield strength with different cooling mediums. |
| Proceedings Inclusion? |
Definite: At-meeting proceedings |