2013 Fiscal Year Final Research Report
Development of novel mechanical processing method of GA steel sheets using stress-induced phase transformation
| Project/Area Number |
23656451
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| Research Category |
Grant-in-Aid for Challenging Exploratory Research
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| Allocation Type | Multi-year Fund |
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| Research Field |
Material processing/treatments
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| Research Institution | The University of Tokyo |
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Principal Investigator |
YAMAGUCHI Shu 東京大学, 工学(系)研究科(研究院), 教授 (10182437)
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| Co-Investigator(Kenkyū-buntansha) |
TANAKA Kazuhiko 東京大学, 大学院・工学系研究科, 技術専門職員 (20456156)
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| Project Period (FY) |
2011 – 2012
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| Keywords | 溶融亜鉛めっき / めっき層 / 応力誘起変態 / 相転移 / ダイヤモンドアンビル / X線回折 / Fe / Zn |
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| Research Abstract |
Based on the hypothesis that plastic deformability appears by the stress-induced transformation from the Fe-Zn intermetallic compounds to hcp/fcc phase, X-ray powder diffraction analysis using a diamond anvil was carried out to estimate the critical pressure of transformation and bulk modulus of the Fe-Zn intermetallics at low- and high-pressure conditions. The samples of zeta and Gamma1 phases collected as the dross phase in the previous study, were examined for the possible presence of phase transitions. No phase transition was observed for the Gamma1 phase up to 30GPa at room temperature, while clear evidence of the phase transition to the hcp phase for the zeta phase was obtained. The phase stability was estimated based on the calculation of the assessed free energy change of mixing (chemical energy) for the Fe-Zn system and estimated values of the bulk modulus and molar volume for the low- and high-pressure phase, and the critical pressures for the phase transitions are proposed.
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