1988 Fiscal Year Final Research Report Summary
A Study on the Formation Process of Long Period Superlattice Structures in Alloys
| Project/Area Number |
62540224
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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 |
固体物性
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
FUJINO Yutaka Department of Nuclear Engineering, Faculty of Engineering, Tohoku University, 工学部, 助手 (60005402)
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| Co-Investigator(Kenkyū-buntansha) |
HIRABAYASHI Makoto Institute for Materials Research, Tohoku University, 金属材料研究所, 教授 (00005836)
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| Project Period (FY) |
1987 – 1988
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| Keywords | antiphase boundary structure in Ag-Mg alloys / order-disorder transition / incommensurate-commensurate transition / charge density wave / フェルミ面のネスティング / 電荷密度波 / ポテンシャル・エネルギー波 / 合金の逆位相長周期構造の安定性 |
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| Research Abstract |
Structural order-disorder transition in metalic alloys have been investigated extensively for more than 60 years from both theoretical and experimental points of view. A number of pioneering experimental works have been performed by the x -ray, the neutron and the electron diffraction measurements. However, order-disorder transitions do not necessarily proceed homogeneously in every portion of the specimen, but it is usually heterogeneous phenomena and develops by the mechanism of nucleation and growth. Thus, it becomes important to do observation not only in reciprocal space but also in real space microscopically.
In the present work, formation process of long period superlattice from disordered phase in Ag-Mg alloys has been studied by means of transmission electron microscopy. It was found for the first time that the ordering was preceded by a metastable state in which ordered and disordered (or weakly ordered) regions were periodically arranged spatially. The nesting of the fermi surface is proposed as the origin of this type of ordering.
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