1993 Fiscal Year Final Research Report Summary
A Study on Fatigue Failure of Bicrystals by means of in site SEM-ECP Observation
| Project/Area Number |
04650647
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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 | Kanazawa University |
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Principal Investigator |
KITAGAWA Kazuo Kanazawa Univ., Faculty of Technology, Professor, 工学部, 教授 (30019757)
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| Co-Investigator(Kenkyū-buntansha) |
HORIKAWA Takesi Ryukoku Univ., Faculty of Science and Technology, Professor, 理工学部, 教授 (30209291)
MONZEN Ryoich Kanazawa Univ., Faculty of Technology, Associate Professor, 工学部, 助教授 (20166466)
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| Project Period (FY) |
1992 – 1993
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| Keywords | Fatigue failure / Persistent slip band / Copper / Single crystal / Bicrystal / Electron channelling pattern / Pre-straining / Grain boundary |
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| Research Abstract |
It has been well known that in soft metals fatigue cracks nucleate at persistent slip band (PSB). However, the relation between the feature of PSB and fatigue behavior is not so clear. In this study, electron channeling pattern (ECP) method was applied to discuss about both tensile deformation and fatigue behavior of Cu single crystals and bicrystals.
1. Fatigue behavior of Cu single crystals subjected to tensile pre-straining was studied by means of push-pull fatigue test.
(1) It is found that pre-straining caused the increase of fatigue life.
(2) Pre-straining caused the fragmentation of PSB.
(3) Both nucleation and growth rate of fatigue cracks was prominently reduced by pre-straining.
(4) The formation of characteristic dislocation structure observed only in fatigued specimens was disturbed by pre-straining.
2. The effect of grain boundary on deformation behavior of bicrystals was studied by means of selected area electron channeling pattern (SACP) method.
(5) Plastic deformation behavior near the grain boundary could be evaluated by this method.
(6) Grain boundary affected zone (GBAZ) depended strongly on the strain incompatibility at the grain boundary.
(7) GBAZ increased with the increase of tensile deformation.
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