Solid-state fabrication of nano-structured oxide dispersion strengthened 14YWT steel for advanced nuclear applications

Enabled Engineering proposes to fabricate nuclear reactor core components using nano-structured oxide dispersion strengthened steel (ODS) via an innovative solid-state technology. The reactor core components for advanced fission and fusion reactor applications demand enhanced elevated temperature properties and radiation damage tolerance. ODS ferritic alloys are often candidate materials for this purpose. Mechanically alloyed 14YWT is one of such nano-structured ODS ferritic steel suitable for advanced fission and fusion reactor applications. However, this material faces very limited manufacturing methods due to its metallurgical attributes. In this project, an innovative process is designed based on the Friction Stir Welding/Processing (FSW/P) principles will be demonstrated for consolidation and fabrication using mechanically alloyed 14YWT powder. The innovative aspect of the project is combining two proven material processing technologies to fabricate nano-structured ODS ferritic steel structures directly into more useful structural forms. These materials can also be directly consolidated on to a substrate for cladding or overlay application. Mechanically alloyed 14YWT have shown to possess exceptional elevated temperature strength and creep properties up to 800 oC while tolerant to radiation embrittlement. The exceptional properties are attributed to their microstructural conditions of oxide nano-clusters featuring very high number density, matrix/particle interfaces capable of trapping helium, and uniform distribution. These microstructural features are specially designed carefully through mechanical alloying method. Use of conventional manufacturing techniques that involve melting will destroy these unique microstructural features. In Phase I, microstructurally sensitive mechanically alloyed 14YWT ODS alloy directly into rods and tubes form in fewer processing steps than any other fabrication route. Successful development and demonstration of the proposed technology for fabricating nano-structured ODS ferritic alloys will be directly impactful on current and future advanced nuclear programs. Most importantly, the proposed manufacturing route has the potential to become a path breaking manufacturing route for microstructurally sensitive materials such as mechanically alloyed powders.