About this Abstract |
| Meeting |
2026 TMS Annual Meeting & Exhibition
|
| Symposium
|
Special Topics in Nuclear Materials: Reproducibility and Uncertainty; Hydrogen Effects; Space and Microreactor Systems
|
| Presentation Title |
Mechanism of Helium-Assisted Hydrogen Retention in Ferritic-Martensitic Steels Under Irradiation |
| Author(s) |
Lihao Shi, Fei Gao |
| On-Site Speaker (Planned) |
Lihao Shi |
| Abstract Scope |
Reduced activation ferritic/martensitic (RAFM) steels are promising structural materials for fusion reactors, but synergistic interactions between helium (He) and hydrogen (H) under irradiation can intensify void swelling and degrade mechanical properties. At 723 K, He traps H atoms to form stable core-shell structures. We propose a mechanism for a He-centered “halo” structure, where H accumulates at the He–Fe interface. Our multiscale simulations reveal that He bubbles promote segregation of Cr and W to the interface, significantly enhancing H binding strength compared to pure Fe. While MD-based kinetic models predict H desorption at 500–600 K (~0.7 eV), experimental observations suggest stronger binding at 723 K. To resolve this, first-principles calculations show that He slabs reduce the segregation energy of Cr and W, promoting solute enrichment and raising H binding energies to ~1.1 eV. These results offer mechanistic insight into He-assisted H retention and inform alloy design strategies for improved radiation tolerance. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Iron and Steel, Computational Materials Science & Engineering, Modeling and Simulation |