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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Copper alloy is the candidate material for cooling components of DEMO divertor. CuCrZr is a first choice among others but issues related to quality control during manufacturing and also among fabrication of the divertor components still remains. CuCrZr also exhibit some weakness against neutron irradiation. One of the keys to deal with these issues is a grain-refinement. Friction Stir Processing (FSP) is a solid-state process where a rotational tool is plunged into the work piece to produce local friction heating inducing complex material flow and intense plastic deformation that leads to grain-refinement, which also may improve irradiation resistivity. The purpose of this study is to examine the applicability of FSP on CuCrZr to improve material’s performances. We first examined the applicability of FSP on Cu materials using OFC and found that the most effective grain refinement and hardness increase can be achieved at the rotation speed of 200 to 300 rpm with a vertical force of 1.5 tons. However, when increasing the rotation speed to 500 rpm, the grain-refinement was not effective enough and hardness did not improve. Based on the results, the examination on CuCrZr alloy was conducted. FSP tests were performed with the rotation speed of 200 to 700 rpm with vertical force of 1.5, 2.0, and 2.5 tons. As a result, grain-refinement and hardness increase were achieved in all conditions, even at 500 rpm and above. However, introduction of cavities and local cracks were seen below 500 rpm. Furthermore, these defects were introduced even at 600 rpm when the vertical force was set to 1.5 ton. The result indicates that the rotation speed and vertical force can be much higher for CuCrZr compared to pure Cu.
会議概要（会議名, 開催地, 会期, 主催者等）
The 14th International Symposium on Fusion Nuclear Technology (ISFNT-14)
Application of friction stir processing on CuCrZr to improve material’s property
