2001 Fiscal Year Final Research Report Summary
Bonding and defect structure of bcc based metals and intermetallics
| Project/Area Number |
12650659
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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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 | KYOTO UNIVERSITY |
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Principal Investigator |
NISHITANI Shigeto Kyoto Univ., Engineering, Assoc. Prof., 工学研究科, 助教授 (50192688)
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| Co-Investigator(Kenkyū-buntansha) |
SUZUKI Tetsuro Tsukuba Inst. of Sci. & Tech., Professor, 総合科学研究機構, 教授 (70045988)
AOKI Masato Gifu Univ., Engineering, Assoc. Prof., 工学部, 助教授 (70192854)
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| Project Period (FY) |
2000 – 2001
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| Keywords | Frenkel method / Monte Carolo simulation / molecular dynamic simulation / Phonon / EAM / Ni-Ti / Ti |
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| Research Abstract |
We calculated adiabatic potentials of bcc-hcp transitions on Ti and B2-B19, transitions on TiNi by the first principles eletronic structure calculations with the electronic finite temperature effect. Furthermore, we newly developed the empirical potentials of (Embedded Atom Method) EAM type by the fitting on the adiabatic potentials, and performed the dynamic simulation at the finite temperatures using this potentials.
The results obtained through this research are followings :
1. The first principles calculation suggested that bcc-Ti shows strong unstablitiy against (110)T$_1$N phonon, and shows deep double well potentials of 0.1 eV.
2. Ti shows the phase stabilities of hcp→(ω)→γ→δ→bcc from the ambient pressure to the higher pressures.
3. Finite temperature effect of electronic systems shows much higher stability of hcp phase than experimental transition temperature.
4. The EAM potential used in the previous papers shows much shallower double well potential than that obtained by the first principle calculations.
5. The more precisely fitted EAM potential shows strong stability of hcp phase under Molecular Dynamic and Monte Carlo simulations.
Thus we concluded that the lattice defects play an important role on the realistic simulations of finite temperature behavior of bcc phase of bcc based lattices.
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