| Project/Area Number |
10650645
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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 | TOHOKU UNIVERSITY |
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Principal Investigator |
MARCEL Sluiter IMR, Tohoku Univ., Assoc. Prof., 金属材料研究所, 助教授 (70292266)
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1999: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1998: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | Interfaces / Alloys / AntiPhase Boundaries / Impurities / Ni-Al-Ti alloys / Interphase Boundaries / Segregation / Cluster Variation Method / クラスター変分法 / 第一原理クラスター変分法(CVM) / 状態図 / 整合界面 / 界面エネルギー / Ni_3Al |
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| Research Abstract |
The classification of impurity behavior at coherent interfaces based on the ternary phase diagram, was studied. Cluster variation method (CVM) calculations were applied to the fcc - L1ィイD22ィエD2 interphase boundary, and the interphase boundary (IPB) energy, concentration profile and segregation, site preference and fcc/ L1ィイD22ィエD2 partitioning were computed. A strong correlation between site preference and partitioning and its temperature dependence was discovered. Moreover, impurities which have repulsive interactions with both A and B segregate away from an IPB and increase its energy. Other types of impurities segregated towards the IPB but lowered its energy only slightly.
The (111) and (100) antiphase boundary (APB) energies in NIィイD23ィエD2Al alloyed with Ti were calculated from first principles. Effective interatomic interactions were computed from electronic total energy calculations and very large scale CVM calculations (using 10s of thousands of correlation functions) were carried out. Ti strongly segregated away from the (111) and (100) APBs and raises the APB energy by as much as 50 mJ/mィイD12ィエD1 per a/o Ti. This result agrees with the (scarce) experimental data.
Sofar the effect of the long-ranged elastic strain was neglected. Therefore, a new way to compute this contribution to the solution energy of impurities was derived and applied to Mg, Sr, Li and vacancies in an fcc Al matrix and applied to antisite defects in GaAs. Somewhat surprisingly, the accurate solution energies were shown to be useful for obtaining enthalpies of mixing as well.
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