The microstructure and tensile properties of ferritic/martensitic steels T91, Eurofer-97 and F82H irradiated up to 20 dpa in STIP-III

摘要

Ferritic/martensitic (FM) steels, T91, Eurofer-97 and F82H, were irradiated up to a maximum displacement dose of 20 dpa (displacement per atom) at temperatures ranging from similar to 120 to similar to 600 degrees C in the 3rd experiment of the SINQ Target Irradiation Program (STIP-III). Tensile tests were performed at 25,400 and 450 degrees C. Microstructural observations show that irradiation-induced defect clusters formed in all investigated specimens, although the densities were low in specimens irradiated at temperatures >400 degrees C. High-density small He bubbles were observed in specimens irradiated to doses greater than or similar to 9 dpa. Small bubble size in specimens of high doses of 17-20 dpa at temperatures >400 degrees C could be attributed low temperatures in the beginning phase of irradiation. The tensile test results demonstrate that not only the specimens irradiated at <350 degrees C but also those irradiated at >400 degrees C show significant hardening effect. The three FM steels present a great similarity in tensile properties under similar irradiation and testing conditions.