1994 Fiscal Year Final Research Report Summary
PREPARATION OF METAL-TIN NANOCOMPOSITE MATERIALS BY MA AND SHOCK CONSOLIDATION
| Project/Area Number |
05650715
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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 |
Material processing/treatments
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| Research Institution | Himeji Institute of Technology |
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Principal Investigator |
YAMASAKI Tohru Himeji Institute of Technology, Faculty of Engineering, Assistant Prof., 工学部, 講師 (30137252)
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| Co-Investigator(Kenkyū-buntansha) |
MIKI Masamichi Himeji Institute of Technology, Faculty of Engineering, Associate Prof., 工学部, 助教授 (00047606)
OGINO Yoshikiyo Himeji Institute of Technology, Faculty of Engineering, Prof., 工学部, 教授 (10047574)
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| Project Period (FY) |
1993 – 1994
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| Keywords | nanocrystalline material, / Fe-TiN, / Ni-TiN, / grain size dependence, / mechanical alloying / shock consolidation / high temperature hardness, |
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| Research Abstract |
Fe-TiN and Ni-Tin nanocrystalline powders were prepared by ball-milling Fe-Ti and Ni-Ti powder mixtures in nitrogen gas, and the milled powders were consolidated by dynamic compaction by using a propellant gun under shock pressures of 38.6 GPa and above. It was found that the hardness of nanocrystalline Fe-63vol.%TiN and Ni-58vol.%TiN dual-phase materials increased with decreasing grain size and reached maximums of Hv=14 GPa, 13GPa and 12GPa at critical grain sizes of 15nm and 10nm, respectively. As the grain size decreased below the critical values, the hardness slightly decreased. the high temperature hardness was also measured at a temperature range from R.T.to 1000K.Softening occurred from low temperatures of about 500K with the grain sizes below 20 nm, and from higher temperatures with larger grain sizes. Softening was believed to occur via diffusional creep. A creep test at constant temperature indicated the existence of a threshould stress in contradiction to the Coble creep.
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