2000 Fiscal Year Final Research Report Summary
Study of dynamical behavior of point defect clusters in neutron-irradiated metals at elevated temperature by electron microscopy
| Project/Area Number |
10450233
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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 | 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) |
NISHIGUCHI Rieko Hiroshima Jogakuin University, Faculty for Human Development, Associate Professor, 生活科学部, 助教授 (60258283)
MUKOUDA Ichiro Faculty of Engineering, Hiroshima University, Research Associate, 工学部, 助手 (70209980)
SUGIO Kenjiro Faculty of Engineering, Hiroshima University, Research Associate, 工学部, 助手 (90294545)
KIRITANI Michio Hiroshima Institute of Technology, Faculty of Engineering, Professor, 工学部, 教授 (70033826)
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| Project Period (FY) |
1998 – 2000
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| Keywords | Sink efficiency of dislocation / Segregation of interstitial cluster / Atomistic process of void formation / Void nucleation / coalescence of vacancy cluster / string-like structure / vacancy ball / Fusion neutron irradiation |
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| Research Abstract |
Following seven items were published during 3 years supports of GRAND-IN-AID FOR SCIENTIFIC RESEARCH (1) A computer simulation study on displacement damage formation near sigma-5 boundary in Silver. (2) Segregation of interstitial clusters near dislocations in FCC metals neutron-irradiated at high temperature. (3) Changes of the dislocation sink efficiency of point defect absorption for the fluence in neutron-irradiated FCC metals at high temperature. (4) Multiplication mechanism of dislocations in neutron-irradiated FCC metals at high temperature. (5) Atomistic mechanism of nucleation and growth of stacking fault tetrahedra (sft) and voids in neutron-irradiated FCC metals at high temperature. (6) Atomistic mechanism of damage structure evolution in fission neutron irradiated FCC metals at high temperature. (7) Atomistic mechanism of damage structure evolution in D-T fusion 14 MeV neutron irradiated FCC metals. In these works, the most significant result is the atomistic mechanism of the formation of vacancy clusters of voids and sft in neutron-irradiated FCC metals at high temperature. TEM observations showed that both of voids and sft form in an FCC metal simultaneously. The number of vacancy that is contained in a void is more than 500, while the number of vacancy in an sft is less than 250. Computer simulation shows that vacancy clusters can move as a cluster through Damask-Dienes-Weizer relaxation after the structure relaxes to string-like cluster. When a number of vacancies in a v-cluster are less than 250, the cluster relaxes to an sft. The sft is the most stable structure in Cu and Ni. When a number of vacancies in a cluster are more than 500, it does not relax to a one (111) platelet due to an anisotropy. A cluster relaxes to a spherical configuration, which are composed by a large number of {111} v-platelets. Its spherical clusters finally relax to a void.
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