About this Abstract |
| Meeting |
2026 TMS Annual Meeting & Exhibition
|
| Symposium
|
Developments in Advanced Nuclear Structural Materials
|
| Presentation Title |
Long-Term Thermal Ageing and Mechanical Evolution of Advanced RAFM Steels for Fusion |
| Author(s) |
Benjamin R. S. Evans, Bethan Hobson, Rebecca Sherwin, Leon Butterworth, James Gibson, David Bowden |
| On-Site Speaker (Planned) |
Benjamin R. S. Evans |
| Abstract Scope |
Reduced activation ferritic-martensitic (RAFM) steels are key candidates for structural components in fusion reactors, but their operational temperature is limited to ~550°C due to precipitate coarsening and loss of creep strength. Advanced RAFM (ARAFM) steels are being developed to extend this limit by refining alloy chemistry and thermomechanical treatments (TMT), particularly through MX-type precipitate strengthening and tungsten solid solution hardening. This work presents mechanical and microstructural analysis of ARAFM steels thermally aged at 600-700°C for up to one year. Thermo-Calc modelling was used to predict equilibrium Laves phase fractions, with microstructural characterisation confirming Laves phase formation and the dependence on initial W content. Experimental results revealed higher-than-predicted Laves phase fractions; coarsening rate simulations using Thermo-Calc suggest that kinetic factors significantly influence phase development during long-term ageing. Nanoindentation screening revealed correlations between ageing conditions, tungsten content, and mechanical degradation. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Nuclear Materials, Environmental Effects, Iron and Steel |