| Project/Area Number |
02452241
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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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 | TOHOKU UNIVERSITY |
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Principal Investigator |
WATANABE Tadao TOHOKU UNIVERSITY, FACULTY OF ENGINEERING, RESEARCH FELLOW, 工学部, 助手 (40005327)
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| Co-Investigator(Kenkyū-buntansha) |
OIKAWA Hiroshi TOHOKU UNIVERSITY, FACULTY OF ENGINEERING, PROFESSOR, 工学部, 教授 (30005243)
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| Project Period (FY) |
1990 – 1992
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| Project Status |
Completed (Fiscal Year 1992)
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| Budget Amount *help |
¥5,100,000 (Direct Cost: ¥5,100,000)
Fiscal Year 1992: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1991: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1990: ¥3,300,000 (Direct Cost: ¥3,300,000)
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| Keywords | Grain Boundary Design and Control / Grain Boundary Character Distribution / Intergranular Brittleness Control / Brittle Materials / Refractory Metal / Intermetallics / Ni_3Al / Brittle Magnets / 強磁性脆性合金 / N_<i3>Al / 粒界設計制御工学 / 脆性材料の強靭化 / 先端高温材料Ni_3Al / 磁場中焼鈍効果 / 高性能磁性材料Feー50%Co合金 / 規則合金・金属間化合物 / 多結晶体の強靭化 / 粒界性格分布制御 / 高融点金属材料 |
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| Research Abstract |
The grain boundary character distribution (GBCD) was investigated on three different types of brittle polycrystalline materials produced by different processing methods: refractory metal molybdenum, directionally solidified Ni_3Al and rapidly solidified Fe-50%Co alloy ribbon.
It has been found that the grain boundary character distribution (GBCD) condition of processing and subsequent heat treatments. It has been reveal ed that intergranular brittleness can be controlled by enhancement of the frequency of low-energy boundaries which are resistant to intergranular fracture, or conversely by reduction of the frequency of high-energy random boundaries which are prone to intergranular fracture.
Other microstructural factors associated intergranular brittleness have been investigated: The grain boundary correlation number and the grain boundary triple junction character have been proposed and experimentally studied for real polycrystalline materials.
The modelling of fracture processes and characteristics in polycrystals has made clear that the fracture toughness and brittle-ductile transition strongly depend on the grain boundary character distribution (GBCD) and geometrical arrangements of grain boundaries. This finding has provided a strong support to the basic concept of toughening of brittle materials by grain boundary design and control achieved in this investigation. The result obtained from this work may be applied to ceramics.
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