| Project/Area Number |
01550547
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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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 | Nagoya Institute of Technology |
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Principal Investigator |
DOI Minoru Nagoya Institute of Technology, Department of Materials Science and Engineering, Associate Professor., 工学部, 助教授 (60135308)
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| Co-Investigator(Kenkyū-buntansha) |
KOZAKAI Takao Nagoya Institute of Technology, Center for Cooperative Research, Associate Profe, 助教授 (80110253)
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| Project Period (FY) |
1989 – 1990
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| Project Status |
Completed (Fiscal Year 1990)
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| Budget Amount *help |
¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 1990: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1989: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Keywords | Precipitation Hardening Alloy / Coarsening / Elastic Energy / Elastic Interaction / Bifurcation Theory / Ostwald Ripening / Splitting / 整合析出物 / 析出組織変化 / 弾性拘束 / ニッケル基超合金 |
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| Research Abstract |
1. In weakly constrained systems such as gamma^' particles in Ni-Si-Al alloy, precipitate coarsening obeys the theories of Ostwald ripening: the mean particle size is proportional to the cube root of the ageing time t, that is, the so-called t^<1/3> law holds, and the size distribution of particles can be scaled with respect to the mean particle size.
2. In strongly constrained systems such as gamma^' particles in Ni-Cu-Si and Ni_4Mo particles in Ni-Mo alloy, unusual coarsening behaviors are observed: coarsening is remarkably decelerated and the particles become uniform in size during the later stage of ageing.
3. Such unusual behavior in strongly constrained systems cannot be explained by the conventional theories of Ostwald ripening but can clearly be explained by the new coarsening theory named Bifurcation theory. In the Bifurcation theory, not only the surface energy but also the elastic energies (especially the elastic interaction energy) are taken into consideration as the driving force for coarsening.
4. In Feーbase ordering alloys, coarsening behaviors of coherent precipitates are similar to those in the Niーbase alloys: in weakly constrained system, coarsening proceeds obeying the conventional theories of Ostwald ripening; in strongly constrained systems, coarsening is remarkably decelerated and the particle sizes become uniform. These behaviors are explained by the Bifurcation theory.
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