Speaker
Haiying Fu
(Fusion System)
Description
Connection between blanket and out-vessel component is essential to fusion reactors. In the present study, electron beam welding was carried out to fabricate a dissimilar-metals joint between a blanket structural material, F82H steel, and an out-vessel component material, 316L steel. Impact properties and deformation behavior of the joint were analyzed after neutron irradiation.
Two types of Charpy V-notch (CVN) impact specimens were used, i.e. 1/3 CVN and 1.5 CVN specimens. The size of the former is 25.4mm×3.3mm×3.3mm; the latter is 20mm×1.5mm×1.5mm. The V-notches were placed at the weld metal (WM), the heat affected zone (HAZ) of F82H, and the base metals (BMs). SSJ type tensile specimens with a gauge size of 5mm×1.2mm×0.35mm were also prepared. Neutron irradiation was carried out on the 1.5 CVN and the tensile specimens with Belgian Reactor II at 300oC up to 5.6±0.1 ×1023 n m-2 (E > 1MeV). Impact tests, tensile tests, and hardness tests were conducted after the irradiation.
Absorbed energy for the joint notched at WM and HAZ of F82H was 77 and 90 J cm-2, respectively, in the impact tests for the 1.5 CVN specimens at room temperature. While, absorbed energy after the neutron irradiation was 74 and 67 J cm-2. Tensile tests and hardness tests exhibited neutron irradiation hardening at the whole part of the joint. The hardening ranged from 22 to 200 VHN and was maximized at the HAZ of F82H. Even the large hardening at the HAZ did not lead to significant degradation of absorbed energy. Microstructural observation indicated that the deformation of the joint is asymmetric and localized in 316L steel. The deformation in 316L likely induced stress relaxation around the WM and HAZ, and was effective to maintain absorbed energy. The asymmetric deformation will be analyzed by using finite element method simulation combined with mechanical property tests.
Co-authors
Haiying Fu
(Fusion System, National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu, Japan)
Hiroyasu Tanigawa
(Japan Atomic Energy Agency, Rokkasho, Aomori, Japan)
Hisashi Serizawa
(Joining and Welding Research Institute, Osaka University, Suita, Osaka, Japan)
Masanori Yamazaki
(Institute for Materials Research, Tohoku University, Oarai, Ibaraki, Japan)
Shuhei Nogami
(Tohoku University, Aoba-ku, Sendai, Japan)
Takeshi Toyama
(Institute for Materials Research, Tohoku University, Oarai, Ibaraki, Japan)
Takuya Nagasaka
(Fusion System, National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu, Japan;SOKENDAI (the Graduate University for Advanced Studies), 322-6 Oroshi, Toki, Gifu, Japan)
Wenhai Guan
(Tohoku University, Aoba-ku, Sendai, Japan)
