2019 Fiscal Year Annual Research Report
Irradiation effects on the performance of the alumina scale formed in FeCrAl ODS ferritic steels
| Project/Area Number |
19K21029
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| Allocation Type | Multi-year Fund |
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| Research Institution | Tohoku University |
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Principal Investigator |
余 浩 東北大学, 金属材料研究所, 助教 (10825871)
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| Project Period (FY) |
2019-04-01 – 2020-03-31
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| Keywords | ODS / alumina scale / irradiation |
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| Outline of Annual Research Achievements |
The TEM microstructure observation focused on dispersed Y-Zr oxide particles inside the single-layer alumina scale was conducted. The Y-Zr-O dispersoids show two shapes, i.e., a common spherical shape, and another unique tadpole-like shape. The formation mechanism was interpreted to be related with a diffusion of the Y/Zr ions driven by the oxygen potential gradient across the alumina scale. Based on the investigation on the oxidation behavior of FeCrAl ferritic ODS alloys, a suitable pre-oxidation condition was obtained. Alumina scale with 0.5um-1.5um thickness were successfully prepared, in which dense Y-Zr oxide particles were dispersed. The pre-oxidized specimens were irradiated with 6.4 MeV Fe3+ at 500oC up to a damage of 3 dpa at the DuET facility in Kyoto University. Both cross-sections and surfaces of the oxidized samples were irradiated. Based on SEM/EPMA characterization, a reliable stability can be confirmed in the Y-Zr dispersed alumina scale.
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