| Project/Area Number |
17360313
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Physical properties of metals
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| Research Institution | Kyushu University |
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Principal Investigator |
YASUDA Kazuhiro Kyushu University, Faculty of Engineering, Associate Professor (80253491)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUMURA Syo KYUSHU UNIVERSITY, Faculty of Engineering, Professor (60150520)
SHIIYAMA Kenichi KYUSHU UNIVERSITY, Faculty of Engineering, Assistant Professor (30243900)
YASUNAGA Kazufumi KYUSHU UNIVERSITY, Faculty of Engineering, Post doctoral Fellow (20404064)
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| Project Period (FY) |
2005 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥15,890,000 (Direct Cost: ¥15,200,000、Indirect Cost: ¥690,000)
Fiscal Year 2007: ¥2,990,000 (Direct Cost: ¥2,300,000、Indirect Cost: ¥690,000)
Fiscal Year 2006: ¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 2005: ¥10,500,000 (Direct Cost: ¥10,500,000)
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| Keywords | Nuclear Material / Radiation Damage / Fluorite Structure / Zicnonia / Ceria / Transmission Electron Microscopy / Selective Displacement Damage / Electronic Excitation / 蛍石型構造 / 酸化物セラミックス / 安定化ジルコニア / 酸化セリウム / 分子動力学法 |
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| Research Abstract |
Oxides with fluorite structure, such as stabilized zirconia and ceria, have potential applications for inert matrix in the nuclear industry. Previously we have found in stabilized zirconia that electron irradiation induces characteristic defect clusters whose nature and growth process is quite different from perfect dislocation loops. The aim of this project is to gain insights into t he formation mechanism of such characteristic defect clusters, and to understand the microstructure stability of fluorite structure ceramics. The followings are the main results and conclusions obtained in this project.
(1) Platelets (or dislocation loops) are formed under electron irradiation on {111} planes in stabilized zirconia, ceria, and calcium fluorite. They accompany strong strain contrast and convert into perfect dislocations when they grow up to a critical size.
(2) Electron energy dependent analysis on the defect clusters in ceria have clarified the formation of oxygen-platelet less than 1250 keV and perfect dislocation loops above 1500 keV.
(3) MD simulations for the relaxation process of oxygen Frenkel pairs have shown that oxygen interstitials aggregate to form two dimensional defects on {111} planes between two Ce-Ce ion planes.
(4) TEM analysis and MD simulations in the present study conclude that the characteristic defect clusters are oxygen (anion)-platelets which are formed under selective displacement damage on relatively lighter element of oxygen (anion).
(5) An important role of low PKAs are suggested on the radiation damage process in fluorite structure ceramics, in which lighter elements of anions aggregate to form defect clusters and multiple dislocations.
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