| Project/Area Number |
14350337
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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 | 一般 |
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| Research Field |
Physical properties of metals
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| Research Institution | Ibaraki University |
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Principal Investigator |
ENOMOTO Masato Ibaraki University, the College of Engineering, Professor, 工学部, 教授 (70241742)
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| Project Period (FY) |
2002 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥9,500,000 (Direct Cost: ¥9,500,000)
Fiscal Year 2004: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2003: ¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 2002: ¥5,900,000 (Direct Cost: ¥5,900,000)
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| Keywords | iron alloy / diffusion / TTT-curve / ferrite transformation / solute drag / bainite |
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| Research Abstract |
For the preceding two years ferrite transformation behaviors and carbide precipitation in Fe-C-Mo and Fe-C-Ni alloys were studied, and the mechanism for incomplete transformation was discussed. Also, a simulation model of diffusion-controlled growth of ferrite was developed incorporating solute drag due to alloying element accumulation at α/γ boundaries.
In the study of the influence of magnetic field on the ferrite transformation in Fe-C-Mo alloys it was found that the bay was shifted to a shorter time and a higher temperature side by applying a magnetic field. This was attributed to the promotion of transformation kinetics below the bay because of the increase in the driving force of transformation due to the applied field. It is considered that the extent of the promotion of ferrite transformation is smaller above the bay because of the concurrent precipitation of carbides in the Fe-C-Mo alloy.
Experimental data on the local condition at moving α/γ boundaries in literature were reviewed. The diffusion spike of an alloying element is often used as a criterion discriminating para-and orth-(or local) equilibrium condition at the boundary. It was found that alloying element partition occurred even in the situation in which the spike width of alloying element in austenite is less than the austenite lattice parameter. This indicates that the diffusion of alloying element significantly occurs along α/γ boundaries and in ferrite. These issues were discussed in the workshop on alloying element effects on austenite decomposition held in Stockholm in December, 2004.
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