量研学術機関リポジトリ「QST-Repository」は、国立研究開発法人 量子科学技術研究開発機構に所属する職員等が生み出した学術成果(学会誌発表論文、学会発表、研究開発報告書、特許等)を集積しインターネット上で広く公開するサービスです。 Welcome to QST-Repository where we accumulates and discloses the academic research results(Journal Publications, Conference presentation, Research and Development Report, Patent, etc.) of the members of National Institutes for Quantum Science and Technology.
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The existing nano-indentation method and developmental micro-tensile testing method are more attractive in accurately defining the irradiation effect on the mechanical behavior and adopted in this study to identify the detailed irradiation behavior of pure tungsten. The pure tungsten (A.L.M.T. Corp., Japan) produced by the powder metallurgy and hot-rolling process has a purity of 99.99 wt%. The irradiation was conducted to a maximum of 18.0 dpa by the TIARA (Takasaki Ion Accelerators for Advanced Radiation Application) at 500 and 800 ℃. The micro-tensile specimens with the gauge section of about 0.8 µm (width) × 0.8 µm (thickness) × 10 µm (length) were machined by a focused ion beam device. The nano-indentation results showed the saturation of irradiation hardening and its irradiation temperature dependence. In the case of 500℃, the indentation hardness of pure tungsten irradiated in TIARA increased with increasing dose, and it reached 6.5 GPa after irradiation to 1.0 dpa. Beyond 1.0 dpa, indentation hardness approached a constant. In the case of 800℃, indentation hardness reached 8.1 GPa by irradiation to 3.0 dpa with an irradiation hardening saturation.