2003 Fiscal Year Final Research Report Summary
Meso-scale analysis for peculiar mechanisms of pyramidal slip in hcp metals
| Project/Area Number |
13650722
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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, Faculty of Engineering, Associate Professor, 工学部, 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) |
2001 – 2003
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| Keywords | dislocation / pyramidal slip / yield stress / hcp metal / core structure / molecular dynamics / computer simulation / anormalous temperature dependence |
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| Research Abstract |
{112^^-2}<<11>^^^-23> second order pyramidal slip was activated in Mg and Mg-Li single crystals by [112^^-0] tensile test in the range of 77K -293K. Yields stress of each crystal increase with increasing temperature, namely anomalous temperature dependence. The pyramidal slip were also activated in the range of 293K -473k and there is no prismatic slip. Activities of pyramidal slip was related to ductility of polycrystalline magnesium.
{101^^-1}<<11>^^^-23> first order pyramidal slip was activated in [0001] tensile and compression. Yield stress of prismatic slip in [112^^-0] and [11^^-00] tension and compression were different in spite of same Schmid's factor.
In molecular dynamics simulation using Lennard-Jones (L-J) potential, the core of (c+a) screw dislocation extended on two {101^^-1} plane. The screw core was moved between {112^^-2} and {101^^-1} by double cross slip.
(c+a) edge dislocation have two type of core structures. Both type of core are not move in negative share and [112^^-0] compression. Partial dislocation cores move by [0001] tensile and compression, and the stress is little different by loading direction. These results shows that motion of (c+a) edge dislocation is affected not only shear stress but also normal stress on slip plane.
From simulation results can summarize the deformation process by secondary pyramidal slip.
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