| Project/Area Number |
62420045
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
Physical properties of metals
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| Research Institution | Hiroshima University |
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Principal Investigator |
SHIMOMURA Yoshiharu Faculty of Engineering, Hiroshima University, Professor, 工学部, 教授 (40033831)
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| Co-Investigator(Kenkyū-buntansha) |
MUKODA Ichiro Faculty of Engineering Hiroshima University, Research Assoc., 工学部, 助手 (70209980)
KITANO Yasuyuki Faculty of Science, Hiroshima University, Assoc. Professor, 理学部, 助教授 (20033855)
FUKUSHIMA Hiroshi Faculty of Engineering, Hiroshima University, Research Assoc., 工学部, 助手 (70156769)
YAMAKAWA Khoji Faculty of Engineering, Hiroshima University, Assoc. Professor, 工学部, 助教授 (50029493)
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| Project Period (FY) |
1987 – 1990
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| Project Status |
Completed (Fiscal Year 1990)
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| Budget Amount *help |
¥14,100,000 (Direct Cost: ¥14,100,000)
Fiscal Year 1990: ¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 1989: ¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 1988: ¥8,000,000 (Direct Cost: ¥8,000,000)
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| Keywords | Cryotransfer Electron Microscopy / Low Temperature Fission Neutron irradiation / Fusion Neutron Irradiation / Structure of Displacement Damage Cascades / Formation of Voids / 2-1 / 2-D Method / Molecular Dynamical Computer Simulation / Cascade Energy Overlapping / 変位カスケ-ド損傷 / 電子顕微鏡 / ボイド・スウェリング / ガン・ダメ-ジ / クライオ・トランスファ-電顕法 / 核分裂中性子照射 / 格子間原子集合体 / 中性子照射損傷組織 / ボイド / 積層欠陥四面体 / 核融合ー核分裂中性子照射損傷の相関 / ニッケル、銅 / 極低温電子顕徴鏡 / 変位カスケード損傷 / replacement collision sequence / 格子間原子 / カスケード・コラプス gun defects (電子顕徴鏡電子銃より飛んでくるイオンによる損傷形成) / クライオ・トランスファー観察 / 中性子照射損傷の素過程 / カスケード・エネルギー・オーバーラップ / 高温中性子照射 |
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| Research Abstract |
In the present work, we developed the cryotransfer technique of electron microscopy of ion- and neutron-irradiated at low temperature. From the experimental results of cryotransfer TEM of ion-, fission-neutron- and fusion-neutron-irradiated metals at low temperature, the following processes are decleared for the formation and evolution of damage cascades in high energy particle-irradiated metals. (1) When the primary snock-on atom is generated in metals, it stops after the collision with other lattice atoms and forms the displacement damage cascade whose the central part is occupied by high concentration of vacancies and is surrounded by the interstitial mantle. Previously it was believed that vacancies agglomerate to form TEM visible clusters (i. e. cascade collapse) and interstitials escapes to nearby sinks. In the present work, it was found that vacancies form sub-electron microscope size of clusters which are invisible by TEM while interstitials form TEM visible clusters. (2) It wa
… More
s clarified that sub-EM sizes of clusters of both vacancy and interstitial type were formed together with visible defects. (3) With increasing the fluence, TEM-invisible clusters tend to change to TEM visible clusters. This occurs due to the assistance of lattice relaxation by emitted energies from new cascades formed nearby previously formed ones. This effect is named by the present scientists "cascade energy overlapping". We believe that this effect is due to the shock-wave emitted at new formed cascade. The details of mechanism is at present studying by molecular-dynamical simulation with super-computer.
(4) Interstitial atoms are emitted intensely towards the outside of cascade core and form TEM visible clusters. The distance was found to be fairly larger when it was compared with that due to the replacement collision sequence. We are proposing that an interstitial atom is transported by surfriding mechanism on the shock wave generated. This may be a reason why many interstitial dot defects form at concentrated place (i. e. groupings). These point defect processes of the formation of damages in metals which are irradiated at high temperature was examined extensively especially for the damage structure evolution and void formation. Less
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