1991 Fiscal Year Final Research Report Summary
Polytypes and stacking faults of intermetallic compounds
| Project/Area Number |
02650471
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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 | Hiroshima Institute of Technology |
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Principal Investigator |
KOMURA Yukitomo Hiroshima Inst. Tech., Fac. of Engineering, Prof., 工学部, 教授 (40033774)
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| Co-Investigator(Kenkyū-buntansha) |
KITANO Y. Hiroshima Univ., Fac. of Science, Assist. Prof., 理学部, 助教授 (20033855)
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| Project Period (FY) |
1990 – 1991
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| Keywords | Laves phase / Polytypes / Stacking faults / X-ray diffraction / Electron microscopy / Intermetallic compound / Mechanical alloying |
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| Research Abstract |
We studied various layer structures of the Mg-base ternary Laves phases and found a close relation between polytypes and electron concentration of the compounds.
In the first year of the project, polytype structures of the Laves phase with heavily faulted area were observed under the high-resolution electron microscope (HREM) and the stacking sequence of the Laves layers could be assigned from the lattice images. X-ray diffuse scattering due to stacking faults was analysed assuming mixed stacking of 2H-9R and 4H-9R-10H structures. Well collimated electron diffraction pattern from these samples showed very sharp spots closely located along the stacking direction instead of diffuse streaks, indicating a long-range correlation of the structure. The results have been reported at the 15th IUCr Congress held in Bordeaux, July 1990.
Dr. Kitano, collaborator of the project, has investigated boundary structures between various polytypes of the Laves phases. He also observed structural images of disclinations in the ordered alloys of Mg-Cd by means of HREM, and found the characteristics of the disclinations.
In the second year, mechanical alloying method (MA) using fine metal powders has been tried in order to prepare alloy powders of Cu-Ni, Fe-Cr, Fe-Ni and Ni-Cr systems by ball milling. Structural changes and lattice defects were investigated as functions of milling time and annealing conditions. FCC solid-solution of Cu-Ni alloys could be made by moderate MA time, however, Fe-Crsigma-phase could not be formed by this method. Unkown X-ray broad diffraction lines were observed in the systems of Fe-Ni and Ni-Cr, so that more detailed investigations are needed for these systems.
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Research Products
(11 results)
