1989 Fiscal Year Final Research Report Summary
Evaluation of Boundary Energies by the Shape of Boundary Inclusions
| Project/Area Number |
63550533
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
金属材料(含表面処理・腐食防食)
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
MORI Tsutomu Tokyo Institute of Technology, The Graduate School at Nagatsuta, Professor, 大学院総合理工学研究科, 教授 (40016259)
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| Co-Investigator(Kenkyū-buntansha) |
HORIE Shiro Tokyo Institute of Technology, The Graduate School at Nagatsuta, Research Associ, 大学院総合理工学研究科, 助手 (90114892)
KATO Masaharu Tokyo Institute of Technology, The Graduate School at Nagatsuta, Associate Profe, 大学院総合理工学研究科, 助教授 (50161120)
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| Project Period (FY) |
1988 – 1989
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| Keywords | Copper / Grain boundary / Boundary energy / Oxygen segregation / Diffusion / Boundary precipitation / Electron radiation damage / Boundary sliding |
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| Research Abstract |
The present investigation determined the (relative) boundary energies of Cu by observing the shapes Of SiO_2 particles on boundaries. The SiO_2 particles on boundaries were introduced by internally oxidizing Cu-Si bicrystals. The preferential precipitation and sliding on boundaries were also examined and were discussed in the light of the boundary energy measurement.
1. The gamma-rheta diagrams for the <110> symmetric tilt, <100> twist and <110> twist boundaries were systematically determined. Several energy cusps were clearly observed. These cusps are described by{111}SIGMA3, {221}SIGMA9 and{113}SIGMA11 in the <110> symmetric tilt, SIGMA5, SIGMA13, SIGMA17, SIGMA29 and SIGMA41 in the <100> twist and SIGMA3 and SIGMA11 in the <110> twist boundaries. The energies of asymmetric <110> boundaries with SIGMA3 and SIGMA11 were also determined as a function of the deviation from the symmetric configuration and were found to sensitively depend on the deviation angle. The energies were also changed by the segregation of oxygen on boundaries. The fast diffusion of oxygen on boundaries was unambiguously shown.
2. The precipitation of Fe-Co particles on boundaries was accelerated when the boundary had a large energy (<110> symmetric tilt and <100> twist boundaries). That is, the larger the energy, the larger the density and size of boundary precipitates and the width of precipitate free zones became.
3. The sink capacity to absorb point defects of <110> symmetric tilt boundaries was investigated by examining foils containing such boundaries under a high-voltage electron microscope and observing the morphologies of secondary defects near the boundaries. High energy boundaries showed larger sink capacities.
4. The sliding on <110> symmetric tilt and <100> twist boundaries was examined. As far as the sliding was in the range of the order of a nanometer, the boundaries with larger energies started to slide at lower temperatures.
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