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 |
Proposed mechanisms influencing radiation-enhanced ductility of irradiated Inconel 718 |
| Author(s) |
David Mcclintock, Maxim Gussev, Tim Lach, Soyoung Kang, Wei Lu, Kinga Unocic, Frank Garner |
| On-Site Speaker (Planned) |
David Mcclintock |
| Abstract Scope |
A post-irradiation examination (PIE) program is maintained at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) for proton beam windows (PBW) and targets to characterize radiation-induced changes and inform decisions on administrative lifetime limits. Recently, tensile tests and microstructure characterizations were performed on PIE samples removed from a solution-annealed Inconel 718 PBW operated to a maximum dose of approximately 9.7 displacements per atom (dpa) and transmutation product concentrations of 1830 appm helium (He) and 7200 appm hydrogen (H). Tensile tests showed a radiation-induced recovery of ductility, uniform and total elongation values increased with increasing dose between 2.5 and 9.7 dpa, and microscopy examinations revealed small (1-3 nm) nanocavities enriched in transmutation products H and He. Differential scanning calorimetry (DSC) and thermal desorption spectrometry (TDS) characterizations showed the stored energy did not increase with increasing dose, while the H and He concentrations did increase with increasing dose. During microstructure characterizations, small nanometer-sized cavities containing H and He were observed throughout the microstructure with short-range order, and a high number density of stacking-faults were observed in deformed regions of the tensile specimens. These results suggest the increase in elongation values with increasing dose may be related to enhanced deformation mechanisms and increased strain-hardening ability. The results from mechanical testing and microstructure characterizations of irradiated 718 specimens are reviewed, and deformation mechanisms are proposed to explain an observed recovery of ductility with increasing radiation dose. |
| Proceedings Inclusion? |
Definite: At-meeting proceedings |