| Project/Area Number |
09650771
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Structural/Functional materials
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| Research Institution | Doshisha University |
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Principal Investigator |
MIMAKI Takuro Doshisha University, Department of Mechanical Engineering, Professor, 工学部, 教授 (20066244)
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| Co-Investigator(Kenkyū-buntansha) |
HASHIMOTO Satoshi Osaka City University, Department of Intelligent Materials Engineering, Professor, 工学部, 教授 (50127122)
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| Project Period (FY) |
1997 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥3,800,000 (Direct Cost: ¥3,800,000)
Fiscal Year 1999: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1998: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1997: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Keywords | Copper / Corrosion / Stress Corrosion Cracking / Ultra-Fine Grain / Equi-Channel Angular Extrusion / Grain Boundary / Dislocation Density / Corrosion Potential / 定電位腐食 / アノード分極 / 粒界転移 / Severe Plastic Defrormation |
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| Research Abstract |
Corrosion tests under a constant potential, stress corrosion cracking (SCC) tests were performed on the ultra fine grained (UFG) copper (avarage grain size : 200 nm) manufactured by Equi-Channel Angular Extrusion (ECAE) technique and on conventional copper specimens. The surface of the UFG copper showed a typical general corrosion. However, the UFG copper has a very high corrosion resistance compared with the conventinal copper (average grain size : 20μ). By Severe Plastic Deformation (SPD), all lattice dislocations flowed out to the grain boundary, so the extremely high dislocation density was formed at the grain boundary of UFG copper. The corrosion potential at the grain boundary of UFG copper was increased by the high dislocation density. On the otherhand, a very strong strain field was induced in the grain interior, so the corrosion potential became high, too. Disolution is controlled by the difference of potential between grain boundary and grain interior.
The susseptibility to stress corrosion cracking of UFG copper was very low compared with conventinal copper and annealed UFG(the same grain size). The gain boundary slidings (GBS) were observed during the tests at room temperature. This GBS acts as a stress relieving sites on the SCC behavior of the UFG copper.
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