| Project/Area Number |
09650755
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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 |
Structural/Functional materials
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| Research Institution | The University of Tokyo |
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Principal Investigator |
ASAKURA Kentaro The University of tokyo, Graduate School, Dept.of Material Science, Research Assistant, 大学院・工学系研究科, 助手 (10111460)
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| Co-Investigator(Kenkyū-buntansha) |
SHIBATA Koji The University of tokyo, Graduate School, Dept.of Material Science, Professor, 大学院・工学系研究科, 教授 (90011121)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 1998: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1997: ¥2,700,000 (Direct Cost: ¥2,700,000)
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| Keywords | High temperature optical microscope / In-situ observation / High speed VTR / Ultra-low carbon steel / Transformation behaviors / gamma*alpha transformation / Transformation temperature / Cooling speed / 高速度画像記録 / 純鉄 / 相変態 / a→γ変態 / α結晶粒径 / ハイスピードカメラ |
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| Research Abstract |
We have developed highly performance-high temperature optical microscope for in-situ observation at phase transformation behaviors of pure irons and ultra-low carbon steels.
The measurement of temperature of the specimens were performed by Pt-Pt/13%Rh thermocouple of 0.2mm phi diameter which was spot welded directly at the edge of specimen. The specimens was cooled with a high temperature optical microscope at cooling rates between 0.5-20ﾟC/sec and about 100ﾟC/sec from 1000ﾟC to room temperature. gamma*alpha transformation behaviors was recorded at 200 frames/sec with high speed VTR system.
Main results were as follows : The gamma/alpha interface crosses the gamma grain during gamma*alpha transformation in pure iron cooled at 0.5-20ﾟC/sec. It is known that a grain size in pure iron is very large comparing with that of usual carbon steels because gamma grain size is originally large and gamma/alpha interface to cross the gamma grain boundary is easy. Therefore, it is thought that the cooling rate dependency on grain size of the a phase becomes small.
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