Mechanical properties and microstructure characterization of Eurofer97 steel variants in EUROfusion program

Under the framework of EUROfusion, we performed comprehensive mechanical and microstructure characterization of ten Eurofer97 steel variants with varying compositions and heat treatment conditions. We characterized the pre-irradiation fracture toughness of the materials along with their Vickers hardness, tensile properties, and microstructure. Compared with standard Eurofer97, the ten variants didn't show a comprehensive improvement of mechanical properties. In addition, the composition and microstructures in some variants are adverse to fracture toughness, such as low C contents, coarse grain sizes, partially tempered martensite, lack of precipitates, and non-uniform distributions of coarse precipitates. Further studies will be performed on the same materials after neutron irradiation.