About this Abstract |
| Meeting |
2027 TMS Annual Meeting & Exhibition
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| Symposium
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Transmutation Effects in Materials in Fission, Fusion, and Spallation Environments
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| Presentation Title |
Gaseous transmutation product softens irradiated Ni-alloy by forming planar complexions |
| Author(s) |
Arya Chatterjee, Caleb Clement, Yongwen Sun, Yang Yang, Jim Ciston, Colin Ophus, Janelle P Wharry |
| On-Site Speaker (Planned) |
Arya Chatterjee |
| Abstract Scope |
This study aims to understand how transmutation-induced gaseous products can reverse irradiation hardening behavior in Ni-based Alloy 625. To simulate transmutation effects, He-ions were implanted in, and pre- and post-irradiation deformation responses were evaluated using nanoindentation. Nanoindentation reveals clear softening in the He-implanted layer compared to the unirradiated Alloy 625, which is contrary to the irradiation hardening typically expected. The unirradiated alloy deforms via deformation twinning, stacking fault (SF) formation, and ε-martensite transformations. But after irradiation, deformation is dominated by dislocation plasticity. In the irradiated microstructure, four-dimensional scanning transmission electron microscopy reveals that implanted He-ions form high-pressure He-vacancy complexes, which first form SFs and then stabilize them by self-organizing into planar complexions. But during subsequent deformation, these SFs unfault, thereby giving the appearance of suppressed irradiation hardening. This indicates that transmutation gas bubbles induce sufficient compressive strain to directly compete with the tensile strains required for “harder” deformation mechanisms. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Nuclear Materials, Characterization, Mechanical Properties |