About this Abstract |
| Meeting |
Materials in Nuclear Energy Systems (MiNES) 2025
|
| Symposium
|
Materials in Nuclear Energy Systems (MiNES) 2025
|
| Presentation Title |
Influence of Dislocations on High Temperature He Embrittlement in Iron-Based Alloys |
| Author(s) |
Zehui Qi, Miguel L. Crespillo, Steven John Zinkle |
| On-Site Speaker (Planned) |
Zehui Qi |
| Abstract Scope |
The structural materials in fusion and Gen IV nuclear reactors face significant degradation risks due to elevated temperatures and radiation environments. One critical degradation mechanism under such conditions is high-temperature helium embrittlement (HTHE). This study investigates the influence of stress and dislocations on helium-induced cavity formation in potential reactor materials. Helium was implanted into 316L stainless steel (SS) and Fe-9%Cr alloys, initially cold-rolled to introduce varying preirradiation dislocation densities, to a peak concentration of ~1800 appm He with He implantation rate of 100 appm/h at 750 °C. Experiments were conducted under both unstressed and elastically stressed (~100 MPa) conditions to assess the role of tensile stress states in embrittlement processes. TEM was used to quantify cavity distributions in both matrix and grain boundary (GB) regions. The findings show that while elastic stress alone does not significantly accelerate cavity formation, the presence of pre-existing dislocations strongly correlates with enhanced HTHE effects. Enhanced nucleation of matrix and GB cavities was observed in cold-rolled 316L SS, and a large void was observed at the GB in cold-rolled Fe-9%Cr. These results highlight the pivotal role of plasticity in HTHE under reactor-relevant conditions. |
| Proceedings Inclusion? |
Undecided |