1991 Fiscal Year Final Research Report Summary
Dispersion Hardening and Super-Plastic Titanium Alloys Prepared by Mechanical alloying, and Their Deformation Modes
| Project/Area Number |
01550553
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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 |
金属材料(含表面処理・腐食防食)
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| Research Institution | Okayama University |
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Principal Investigator |
HIDA Moritaka Okayama University Faculty of Engineering Professor, 工学部, 教授 (90023134)
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| Co-Investigator(Kenkyū-buntansha) |
SAKAKIBARA Akira Okayama University Faculty of Engineering Associate Professor, 工学部, 助教授 (40033245)
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| Project Period (FY) |
1989 – 1991
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| Keywords | Mechanical Alloying / Titanium Ball-Mill / Ti-Mo Solid Solution / Ti-base TiN Dispersion Alloy / Ti-9.5V-2.5Mo-3Al Alloy / HIP Consolidation / Contamination / Hardness |
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| Research Abstract |
The following results obtained for the past three years are very important to clarify the mechanochemical potentials about mechanical alloying(MA)and the limits of the application to materials engineering.
1)As long as the ball milling energy is high enough, solid solution alloy is completely performed even for the alloy system being difficult to prepare by melt method.
2)The fatal defect of MA is contamination from the ball mill made of steel. The titanium ball mill is used to prevent the contamination. But the potential energy of MA drops so as to be proportional to the weight of the balls.
3)As titanium is chemically active, the 5N and 4N purity carrier gases, Ar, N_2 etc., should be'purified with sponge titanium heated above 523K in order to prevent the surface oxidation of powder. The deoxidation of Ar gas promotes sticking of MA powder to the ball mill. The deoxidized N_2 has a potential of solving 8mass%N as nitride TiN in Ti matrix for 144ks MA with Ti ball mill. TiN is dissociated to Ti-N solid solution at high pressure.
4)When the mixed powder of Ti-9.5V-2.5Mo-3AI is mechanically alloyed for 432ks with Ti ball mill, the alloy system becomes to beta solid solution powder expected to be super-plastic in bulk sample.
5)The consolidation of some kinds of MA powder is tried by HIP treatment(1270K, 100MPa). Failures of HIP sample made of MA powder of Ti-Mo, Ti-V-Mo-Al, Ti-N take place during cooling to 300K and reducing pressure to O. lMPa. The after effect of MA and HIP treatments cause drastically decreasing the ductility of the consolidated samples.
6)The engineering application of MA depends on the success of the consolidation of powders which remains ductility as the bulk sample.
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Research Products
(12 results)
