| Project/Area Number |
16560580
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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 |
Physical properties of metals
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| Research Institution | Kumamoto University |
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Principal Investigator |
ANDO Shinji Kumamoto University, Graduate School of Science and Technology, Associate Professor, 大学院・自然科学研究科, 助教授 (40222781)
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| Co-Investigator(Kenkyū-buntansha) |
TONDA Hideki Kumamoto University, Faculty of Engineering, Professor, 工学部, 教授 (90040386)
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| Project Period (FY) |
2004 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 2005: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2004: ¥2,600,000 (Direct Cost: ¥2,600,000)
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| Keywords | dislocation / pyramical slip / yield stress / hcp metal / core structure / molecular dynamics / computer simulation / anormalous temperature dependence / 非底面転位 / 降伏応力 |
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| Research Abstract |
Second order pyramidal slip was activated in Mg-0.1Zn and Mg-01.Al alloy single crystals by <11-20> tensile test in the range of 77K-473K. Yields stress of the pyramidal slip increased with Zn addition and the stress decreased with Al addition. <0001> compression test of pure Mg single crystals was also carried in the range of 77K-473K. Second order pyramidal slip was activated in compression in all range. The yield stress increased with increasing temperature, namely anomalous temperature dependence was observed. The pyramidal slip were also activated in the range of 293K-473k and there is no prismatic slip. The yield stress in compression is 1.5-2 times higher than the stress in <11-20> tensile. This results shows that the yield stress of pyramidal slip doesn't obey Schmid's law.
To investigate above anormalous behavior between compression and tension, molecular dynamics simulation of the (c+a) edge dislocation core structure on pyramidal plane was carried. The yields stress of pyramidal slips in <0001> compression is lower than that in <0001> tensile. This behavior is contributed to asymmetrical core structure of (c+a) edge dislocation.
Relation between active slip systems and applied stress direction was investigated by molecular dynamics simulation. <0001> tensile test was carried with a hcp model crystal which have 80000 atoms and sharp notch as dislocation source. In this case, (c+a) dislocation was emitted from the notch and {10-12} twin was also observed. In a case of <10-10> tensile, a-dislocation was slipped on prismatic plane. These results show that there are clearly dependence of tensile axes and active slip system in hcp crystals.
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