| Project/Area Number |
04452043
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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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 | Nara Women's University |
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Principal Investigator |
NAGASAWA Akira Nara Women's University, Department of Physics, Professor, 理学部, 教授 (80046961)
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| Co-Investigator(Kenkyū-buntansha) |
SUZUKI Toshiharu Nara Women's University, Department of Physics, Associate Professor, 理学部, 助教授 (60110805)
MATSUO Yoshie Nara Women's University, Department of Physics, Professor, 理学部, 教授 (00031675)
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| Project Period (FY) |
1992 – 1993
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| Project Status |
Completed (Fiscal Year 1993)
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| Budget Amount *help |
¥5,700,000 (Direct Cost: ¥5,700,000)
Fiscal Year 1993: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1992: ¥5,000,000 (Direct Cost: ¥5,000,000)
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| Keywords | beta-phase alloy / Premartensitic state / Phonon dispersion relation / Lattice instability / Stress induced Transition / Anharmonicity / Interplaner force constant analysis / Vacancy / 3次弾性定数 |
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| Research Abstract |
We have revealed the following characteristics of lattice instability in the premartensitic state of some beta-phase alloys.
1)Phonon behaviors of the [110]TA_1 branch of Cu_3Al(+Pd) alloy under the [001] pressure indicate that the lattice instability toward the 18R martensite is induced in the premartensitic state by such a pressure.
2)We measured the [110]TA_1 phonon dispersion relation in a wide range of temperature and proved that the lattice instability toward the 18R martensite is only a characteristic of the Heusler phase. The 2/3[110] elastic peak is not precursor but is originated from quenched vacancies.
3)Temperature dependence of the [110]TA_1 phonon dispersion relation of AuZn alloy suggests that the beta_1 phase is instabilized by cooling toward a stacking structure with three-layr-period. In fact, we have found the martensite with the zeta_2' structure.
4)We measured the [110]TA_1 phonon dispersion relation in the premartensitic state of AgZn, AuCuZn_2 and NiAl alloys under the [001] pressure. AgZn does not exhibit any lattice instability, while AuCuZn_2 and NiAl show the lattice instability toward the respective martensites formed by cooling. The 1/6 dip observed in the [110]TA_1 phonon branch in NiAl is not the martensitic precursor.
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