1. Effects of helium production, displacement damage on mechanical properties and surface acoustic wave in austenitic stainless steels and martensitic steel
- Author
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Kazumi Aoto, Sin-iti Kitazawa, Eiichi Wakai, Nariaki Okubo, Takeo Iwai, Shigeru Takaya, Yuji Nagae, Hiroaki Abe, and T. Omata
- Subjects
010302 applied physics ,Austenite ,Nuclear and High Energy Physics ,Materials science ,Materials Science (miscellaneous) ,Surface acoustic wave ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Microstructure ,01 natural sciences ,Fluence ,Focused ion beam ,lcsh:TK9001-9401 ,Nuclear Energy and Engineering ,Transmission electron microscopy ,0103 physical sciences ,Hardening (metallurgy) ,lcsh:Nuclear engineering. Atomic power ,Irradiation ,Composite material ,0210 nano-technology - Abstract
The effects of helium production, displacement damage on mechanical properties and microstructures were investigated in some specimens such as austenitic stainless steels of SUS304 and SUS316 and a high chromium martensitic steel of HCM12A steels irradiated in a high fluence irradiation facility (HIT) of the University of Tokyo. The simultaneous dual ion (nickel plus helium ions) irradiations were adopted to simulate nuclear irradiation environments such as fast reactor and fusion reactor at HIT to 1 or 10 dpa and to 0, 1, 10, and 100 appm-He at 500, 550, and 600 °C. Thin foils for a transmission electron microscopy (TEM) were prepared with a focused ion beam (FIB) micro-sampling system. After the irradiation, the microstructures were observed by a transmission electron microscope and the irradiation hardening was measured by nano-indentation technique. In this study, the efficient of non-destructive measurement method of surface acoustic wave (SAW) excited by laser beam on the detection of radiation hardening behavior was also examined. Irradiation hardening was observed and the increment was tended to increase with dpa and He/dpa, which was especially effective in the condition of 100 appmHe/dpa even at 550 °C. Non-linear effect on amplitude of the excited SAW was also observed on the ion irradiated materials, and the propagation velocity of SAW was tended to be increased with irradiation dose. It was found that the behaviors of SAWs results were correlated with the changes of mechanical properties. Keywords: Irradiation hardening, Surface acoustic wave, Helium, Displacement damage, He/dpa, Austenitic stainless steel
- Published
- 2018