About this Abstract |
| Meeting |
11th International Symposium on Superalloy 718 and Derivatives 2026: Legacy, Innovations, and Future Directions
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| Symposium
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Superalloy 718 and Derivatives 2026: Legacy, Innovations, and Future Directions
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| Presentation Title |
Microstructure Evolution of René 65 During the Initial Stages of Industrial-Scale Ingot Conversion |
| Author(s) |
Karen Ni, Chen Shen, Nicholas J. Krutz, Richard DiDomizio, Timothy Hanlon, Justin R Bennett, Bryan Raymond, Kevin Shoemaker, Ian Spinelli, Marija Drobnjak, Krystal Dickson |
| On-Site Speaker (Planned) |
Karen Ni |
| Abstract Scope |
Industrial-scale cast and wrought materials such as René 65 (R65), a γ’ strengthened nickel-base superalloy, must undergo thermomechanical processing to convert the initial ingot grain structure to a refined billet grain structure improving its forgeability, inspect-ability, and mechanical properties required for part operation. The early stages of a conversion process were investigated on an industrial-scale homogenized R65 ingot with lab-scale compression samples extracted at two radial locations to capture the center to edge microstructural variation. The flow stress, dynamic recrystallization (DRX), and post-dynamic recrystallization (PDRX) responses were evaluated across the processing conditions of 1700°F to 2050°F and across strain rates of 0.00032 s-1 to 3 s-1. To evaluate the microstructure of the large number of samples within this processing window, a semi-automated imaging procedure based on etched optical images was utilized for high throughput characterization. Selected samples were assessed using electron backscatter diffraction (EBSD) coupled with Energy Dispersive X-Ray Spectroscopy (EDS), and the combined characterization techniques showed a spatially inhomogeneous dynamic recrystallization response. Grains containing abundant amounts of recrystallization were adjacent to grains with minimal recrystallization. Dynamic necklace recrystallization and particle stimulated intragranular heterogenous recrystallization behaviors were observed. Higher levels of strain led to higher dynamic recrystallization percentages and compression at higher temperatures resulted in coarser dynamic recrystallized grain sizes. Following a thermal exposure to assess the post-dynamic recrystallization behavior, the microstructures of all samples were nearly fully recrystallized, despite low levels of dynamic recrystallization in several samples. |
| Proceedings Inclusion? |
Definite: At-meeting proceedings |