| Project/Area Number |
19760063
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Materials/Mechanics of materials
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| Research Institution | Kanazawa University |
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Principal Investigator |
WATANABE Chihiro Kanazawa University, 機械工学系, 准教授 (60345600)
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| Project Period (FY) |
2007 – 2009
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| Project Status |
Completed (Fiscal Year 2009)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥300,000)
Fiscal Year 2009: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2008: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2007: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | 機械材料 / 金属疲労 / Sc含有Al合金 |
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| Research Abstract |
The effects of small amount of Sc addition on the fatigue properties of Al-Mg and Al-Mg-Si alloys at elevated temperatures have been examined. Cyclic softening after initial hardening is found in the Al-Mg alloys with small Al_3Sc particles, but no cyclic softening takes place in the alloys with larger particles. The cyclic softening is explained by a loss of particle strengthening through particle shearing within strongly strained slip bands. The larger Al_3Sc particles have a stronger retardation effect on the formation of fatigue-induced stable dislocation structure than small particles even at a high temperature. After peak-aging treatments, the Al-Mg-Si alloys has fine lath-shaped β' precipitates. In the Sc-containing Al-Mg-Si alloy, spherical Al_3Sc precipitates of about 11 nm in diameter are co-existed. The Al-Mg-Si alloy with Sc exhibits cyclic hardening to saturation, while the alloy without Sc shows clear cyclic softening after initial hardening. In the Sc-bearing Al-Mg-Si alloy, owing to the existence of non-shearable Al_3Sc precipitates, dislocations were uniformly distributed, resulting in the improvement of fatigue life.
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