Magnetic characterization of ODS-Eurofer steel: Remanent magnetization and magnetostriction behavior

Oxide dispersion strengthened ODS-Eurofer steel is a promising candidate for structural applications in future nuclear fusion reactors. Samples of 9Cr-ODS-Eurofer steel were cold rolled up to 80% thickness reduction and annealed up to 1350 °C for 1 h. The microstructural changes of the annealed samples were followed by magnetic measurements taken at room temperature. In comparison with the coercive field (Hc), the remanent magnetization (Mr) and longitudinal magnetostriction (λlong) behaviors can be explained only if we assume some interaction between pinning sites and residual stresses in the material. It was found that Hc, Mr, λlong, and hardness display the same trend. At the expected fusion DEMO reactor operating conditions (around 650 °C and maximum magnetic field of 6 T), the magnetostrictive deformation would not surpass 15 ppm (15 μm in 1 m).