Grain size manipulation of the Eurofer steel via mechanical alloying

The Eurofer steel has been developed as a reference structural material for future nuclear fusion power plants. The conventional variant of the steel is produced by casting and homogenization by forging. The main method of strengthening the steel is by refining the martensitic grain. For that, several conventional grain size reduction strategies are available such as hot rolling, cold rolling or multiple normalizing. Alternative methods of producing Eurofer steel from powder using additive technologies lose a vital tool for controlling the grain size of the sintered steel. This study focuses on the preparation of ferritic-martensitic Eurofer steel using a powder metallurgy approach, combining mechanical alloying and spark plasma sintering. The alloying process yielded four fractions with distinct powder particle size distributions. The microstructural analyses revealed grain size variations of the produced steel influenced by the original powder particle size, affecting tensile strength and ductility. Furthermore, the study explores the impact of powder particle size manipulation on grain size and mechanical properties, demonstrating its efficacy in refining the Eurofer steel microstructure beyond traditional normalization methods. The findings indicate that powder metallurgy allows for precise control over the grain size offering a versatile approach to tailor the mechanical properties of the Eurofer steel. Graphical abstract