| Project/Area Number |
10555226
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Structural/Functional materials
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
WATANABE Tadao Tohoku University, Graduate School of Engineering, Professor, 大学院・工学研究科, 教授 (40005327)
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| Co-Investigator(Kenkyū-buntansha) |
IGARASHI Yuichiro Tohoku University, Graduate School of Engineering, Research Assoc., 大学院・工学研究科, 助手 (80005347)
TSUREKAWA Sadahiro Tohoku University, Graduate School of Engineering, Assoc. Professor, 大学院・工学研究科, 助教授 (40227484)
FUJINO Yutaka Tohoku University, International student affairs office, Professor, 留学生センター, 教授 (60005402)
KAWAHARA Koichi Tohoku University, Graduate School of Engineering, Research Assoc., 大学院・工学研究科, 助手 (00302175)
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| Project Period (FY) |
1998 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥11,300,000 (Direct Cost: ¥11,300,000)
Fiscal Year 2000: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1999: ¥4,400,000 (Direct Cost: ¥4,400,000)
Fiscal Year 1998: ¥5,600,000 (Direct Cost: ¥5,600,000)
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| Keywords | ultra-high temperature material / intergranular oxidation / oxidation embrittlement / grain boundary character distribution (GBCD) / grain boundary segregation / grain boundary engineering / EBSP / silicon carbide / 耐熱材料 / 鉄基合金 / 磁性 / 非酸化物セラミックス / 粒界3重点 / 粒界の化学的性質 / 高融点金属 / 後方散乱電子線回折法 |
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| Research Abstract |
This project was conducted for development of heat- and oxidation-resistant materials at ultra-high temperatures through grain boundary and interface architecture. Main results obtained are as follows.
1. A study on grain boundary oxidation and oxidation induced brittleness in Ni-Fe alloy : The effect of grain boundary structure on intergranular oxidation was investigated in a Ni-Fe alloy. We have found that intergranular oxidation preferentially takes place at random boundaries, while low-Σ coincidence boundaries such as Σ3, Σ11, Σ19 possess excellent oxidation resistance. Grain boundary engineering was applied to controlling oxidation induced embrittlement in polycrystalline Ni-Fe alloy by taking account of the grain boundary character distribution (GBCD) as well as the grain boundary density (grain size). The presence of an optimal grain boundary microstructure for this purpose has been predicted.
2. Effect of grain boundary microstructure on mechanical property and grain boundary seg
… More
regation induced embrittlement in nanocrystalline nickel : We have found that the microhardness in nanocrystalline nickel decreases not only with increasing the frequency of coincidence boundaries but also with increasing triple points at which the coincidence boundaries are interconnected. In addition, we have confirmed that the grain boundary segregation induced brittleness can be improved by controlling the GBCD and the grain size.
3. A study on Control of oxidation induced embrittlement in Silicon Carbides : The effect of dopants (Mg, Al, P) on the grain boundary microstructure was studied in β-silicon carbide. We have succeeded in changing the GBCD in β-silicon carbide by controlling dopants. In addition, we have evaluated oxidation induced embrittlement by 3-point bending test at room temperature using some specimens oxidized at different temperatures and oxygen partial pressures. It has been found that the oxidation embrittlement in β-silicon carbide can be effectively improved by decrease in the frequency of random boundaries and the grain size. Less
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