2002 Fiscal Year Final Research Report Summary
Development of phase diagram calculating codes based on bond order potentials
| Project/Area Number |
11555161
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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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) |
MATSUMIYA Toru Nippon Steel Corp., Fellow, 先端技術研究所, 部長
AOKI Masato Gifu Univ., Engineering, Assoc. Prof., 工学部, 助教授 (70192854)
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| Project Period (FY) |
1999 – 2002
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| Keywords | Phase diagram / Frenkel method / Vibrational entropy / bcc-hcp transition |
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| Research Abstract |
For the purpose of reliable calculations on free energies on elemental p-T diagram and binary phase diagram, we checked the effects of
1. many body interactions of enthalpy changes, and
2. anharmonic vibrational entropies.
1. Many body interactions
The enthalpy changes arised from the environment dependency of chemical bondings are predicted by bond order potentials based on Tight binding approximation. We developed parallel code and applied them to predict formation enthalpies of dilution limit alloys.
2. Anharmonic vibrational entropies
Thermal expansion and allotropic phase transitions are controlled by anharmonic effects of vibration entropies, which is reliably estimated by Frenkel method in Monte Cargo simulations. We developed also paralled code and applied it on bcc-hcp transition in Ti.
Based on these simulations we also developed new method of reliable prediction on free energy changes of precipitate nucelations.
We opened some of these developed codes in public, and the others are in progress.
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