| Project/Area Number |
60550455
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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 |
Physical properties of metals
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| Research Institution | University of Tsukuba |
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Principal Investigator |
SUZUKI Tetsuro Institute of Applied Physics, University of Tsukuba, 物理工学系, 教授 (70045988)
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| Co-Investigator(Kenkyū-buntansha) |
OTSUKA/KAZUHIRO Institute of Material Science, University of Tsukuba, 物質工学系, 教授 (50029881)
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| Project Period (FY) |
1985 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1986: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1985: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | Martensitic Transformation / Phonon Dispersion Relationship / Uniaxial Stress / 非線型格子波 / 自由エネルギー / ソリトン |
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| Research Abstract |
Dependence of the phonon dispersion relation on the uniaxial stress of the transverse acoustic lattice waves, TA mode, both in the parent phase(<beta>_1) and in the martensitic phases (<gamma>'_1,<beta>''_1 and <alpha>'_1)of Cu-Al-Ni alloys were measured. The phonon dispersion relation in the martensite <gamma>'_1 was independent of the uniaxial stress up to 275 MPa. Furthermore, the phonon dispersion relations in the martensites <beta>''_1 and <alpha>'_1, which were induced by the uniaxial stress from the martensite <gamma>'_1, were very similar to that in <gamma>'_1. The phonon dispersion relation in <gamma>'_1 softened slightly by heating from 10 K to A_s. By applying uniaxial stress, the phonon dispersion curve in the parent phase (<beta>_1) softened slightly around q values of (2/3)q_<max> and of the Brillouin zone boundary.
The martensitic transformation is interpreted as a condensation process of solitons instead of phonons. A twin boundary in the martensitic phase is a soliton. The asustenitic phase at sufficiently high temperature consists of dynamic solitons. A finite bias field is required to stabilize dynamic solitons in the austenite. The premartensitic structure consists of solitons stabilized by the bias field associated with the composition fluctuation. The martensitic phase consists of the solitons stabilized adiabatically by the bias field associated with the martensitic transformation itself.
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