| Project/Area Number |
11650676
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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 | Tokyo Institute of Technology |
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Principal Investigator |
KAJIHARA Masanori Tokyo Institute of Technology, Dept. Materials Science & Engineering, Assoc. Prof, 大学院・総合理工学研究科, 助教授 (10161035)
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| Co-Investigator(Kenkyū-buntansha) |
KATO Masaharu Tokyo Institute of Technology Dept. Innovative & Engineered Materials, Prof., 大学院・総合理工学研究科, 教授 (50161120)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2000: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1999: ¥2,900,000 (Direct Cost: ¥2,900,000)
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| Keywords | Boundary energy / Bicrystal / Tilt boundary / Mechanical property / Silica particle |
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| Research Abstract |
A silica particle observation method was utilized to determine experimentally the boundary energiesof Σ9 and Σ11 [110] asymmetric tilt boundaries with misorientation angles of θ=38.9 and 50.5°, respectively, in Cu for various inclination angles between φ=0 and 90°. The present method has nodrawbacks which are inevitable in boundary grooving and tri-junction methods. In the boundary energy versus inclination angle diagram for the Σ11 boundaries, three deep cusps exist at φ=10, 64.8 and 90° whereas a shallow cusp appears at φ= 35.3°. On the other hand, in the case of the Σ9 boundaries, the boundary energy rather monotonically decreases with increasing inclination angle, and then reaches to the minimum value at φ=65°. As the inclination angle becomes greater than 65°, the boundary energy increases slightly.
Copper bicrystals with the Σ9 boundaries were doped with bismuth at 1173 K for 48 h and then homogenized at 1173 K for 48 h. Tensile tests of these bicrystals were carried out on an Instron-type machine at 77 K and room temperature along the direction normal to the grain boundaries. At room temperature, the bicrystals with φ=0 to 32.8° fracture in an intergranular manner, whereas those with φ=54 to 90° fracture in a transgranular manner. On the contrary, the transgranular fracture was observed at φ= 54 to 64° at 77 K.Such dependence of the fracture manner on the inclination angle can be accounted for by the inclination angle dependence of the boundary energy.
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