About this Abstract |
| Meeting |
Materials in Nuclear Energy Systems (MiNES) 2025
|
| Symposium
|
Materials in Nuclear Energy Systems (MiNES) 2025
|
| Presentation Title |
Coupled Evolutions of Grain Boundaries and Grain Interiors in Alloys Under Irradiation |
| Author(s) |
Sara Wonner, Sourav Das, Amit Verma, Yen-Ting Chang, Nicholas Saunders, Daniel Vizoso, Semanti Mukhopadhyay, Arun Devaraj, Remi Dingreville, Marie A. Charpagne, Robert S. Averback, Pascal M. Bellon |
| On-Site Speaker (Planned) |
Pascal M. Bellon |
| Abstract Scope |
Irradiated alloys display complex microstructures comprised of structural defects, e.g., grain boundaries (GBs) and dislocation loops, and chemical heterogeneities, e.g., segregated layers and nanoprecipitates. The thermodynamic and kinetic coupling between these sub-systems plays a determinant role in microstructural evolution under irradiation. This is illustrated in two cases focusing on radiation-induced segregation (RIS) and precipitation (RIP) at GBs. The first case concerns the effect of GB character on RIS in an extensively studied engineering material, 316L stainless steel with macroscopic grain size, subjected to 2 MeV proton irradiation at 360˚C to 4 dpa. RIS levels and patterns are characterized using STEM-EDS and atom probe tomography (APT) to contrast high-angle GBs and coherent twin GBs (CTWGBs). While pristine CTWGBs may be poor sinks for point defects, it is shown that this assumption is no longer valid after ≈ 1 dpa, due to the build-up of structural defects such as steps and dislocation loops at these CTWGBs. The second example concerns the coupling of RIS and RIP with grain evolution in model nanocrystalline Ni-Si and Ni-Ge undersaturated thin film alloys, irradiated with 2MeV Ti ions at 450˚C to 550˚C to 30 dpa. STEM and APT analysis demonstrate that these alloys can reach a steady state, where nanoprecipitates from different phases and different sizes coexist at GBs and inside the grains. Phase field modeling is employed to rationalize these evolutions. SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525. |
| Proceedings Inclusion? |
Undecided |