Tensile and low-cycle fatigue properties of solution annealed type 316L stainless steel plate and TIG-weld exposed to 5 dpa at low-temperature (42 °C)

The austenitic stainless steel type AISI 316 L was selected as the main structural material of the next-step International thermonuclear experimental reactor (ITER) fusion device, i.e., the first wall, blanket modules, and vacuum vessel components. Although this steel was extensively investigated under different aspects, most results concern irradiation temperatures above 300 °C. In the present work, tensile and fatigue specimens were irradiated in the BR2 materials testing reactor at 42 °C up to a maximum neutron fluence of 8×10²¹ n/cm² (E>0.1 MeV), corresponding to 5 dpa. The European reference AISI 316L in the solution annealed condition and the TIG-metal deposit were tested in the baseline and irradiated conditions. The tensile specimens were tested at 25 °C, 250 °C and 450 °C, while the low-cycle fatigue tests were performed at room temperature. The tensile test results obtained in this work are consistent with published data: substantial radiation hardening combined with some reduction of elongation. No specimen orientation effect could be evidenced. The amount of hardening decreases with increasing test temperature. By contrast, the low-cycle fatigue data show no or little effect of irradiation, independent from irradiation and testing conditions. No major difference was found between the plate and the weld metal.