Pre- and post-irradiation mechanical properties of ferritic-martensitic steels for fusion applications: EM10 base metal and EM10/EM10 welds☆

Abstract The comparison of EM10 base metal with other commercial ferritic-martensitic nuances (EM12, F17, 1.4914, T91, HT9) shows that the fully martensitic steels exhibit the lowest swelling and DBTT values and that, in this class of materials, the unstabilized 9Cr EM10 displays a particularly good behaviour from a mechanical and microstructural point of view. Pre- and post-irradiation characterizations were performed on TIG and electron beam EM10/EM10 welds in as-received or “stress-relieved” conditions. After irradiation at 65 dpa and 732 K in Phenix, it is shown that the mechanical properties of the irradiated EB (annealed or not annealed) and annealed TIG welds are not very different from the values obtained on the irradiated base metal. On the contrary, the as-welded TIG samples exhibit a higher mechanical resistance related to a lower ductility.