| 研究課題/領域番号 |
19K15477
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| 研究機関 | 東京大学 |
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研究代表者 |
楊 会龍 東京大学, 大学院工学系研究科(工学部), 特任助教 (10814254)
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| 研究期間 (年度) |
2019-04-01 – 2022-03-31
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| キーワード | Irradiation hardening / Crystal orientation / texture / Zr alloy / Degradation behavior / ODS steel |
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| 研究実績の概要 |
As described in the summary for FY2019, we previously developed the method to correlate the irradiation induced hardening with the crystal orientation with the application of ion-accelerator irradiation, nano-hardness test, and orientation imaging microscopy analysis. Using this method, the crystal dependent irradiation induced hardening was confirmed in both zirconium (Zr) based alloys and oxide dispersion strengthened (ODS) ferritic steels. In FY 2020, for ion-irradiated Zr alloys, the microstructure characterization of irradiation defect was conducted by transmission electron microscopy (TEM). The formation of high density of dislocation loops was confirmed and analyzed to be responsible for the hardness increment after irradiation. Also, the specimens from the other planes were prepared and subjected to the irradiation, so as to achieve a full-range crystal orientation dependent hardening in Zr alloy. In the case of ODS steel, the hardening behavior due to high temperature irradiation and the deformation microstructure beneath the indentation were investigated. Results showed that a higher temperature would give rise to a mitigated hardening, whereas the temperature did not alter the tendency of crystal dependent irradiation induced hardening. TEM observation of the microstructure beneath the indentation reveals that the depth of the deformation affected zone varied with orientation, and that the dislocation-grain boundary interaction was distinct respective to the geometric relation between grain boundary and indenter impression direction.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
In FY2020, the effect of microstructure on the irradiation induced hardening in Zr alloys was investigated. The role of grain boundary and second phase boundary in the evolution of irradiation defect formation was discussed based on the detailed TEM observation. Meanwhile, the temperature effect and the deformation behavior beneath the low-indexed grains after nano-indentation tests were investigated in ODS ferritic steel, to achieve a depth understanding of the inhomogeneous irradiation induced hardening in the structural component materials for the nuclear applications.
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| 今後の研究の推進方策 |
In FY2021, the following research tasks are planned:
(1) For hcp-latticed Zr based alloys, the transmission electron microscopy examination will be performed to observe the dislocation distribution beneath the indentation tested at low-indexed grains, to understand the correlation of crystal orientation, deformation mechanism, irradiation defects formation.
(2) Based on all the tested specimens, including hcp-Zr alloy, bcc-steel, room temperature and high temperature irradiation, various microstructural features, the factors dominating the inhomogeneous irradiation induced hardening in structural materials for nuclear applications will be discussed and summarized.
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| 次年度使用額が生じた理由 |
The business trip planned to attend the international and domestic conferences were cancelled due to the COVID-19 pandemic in the previous year.
For the last fiscal year, the budget for the next year will be planned to attend several conferences to present the important results achieved in this project. Also, some necessary consumable items, especially about the specimen preparation and FIB/TEM characterization will be planned to ensure the implement of the research tasks.
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