1998 Fiscal Year Final Research Report Summary
Improvement of mechanical properties of short fiber reinforced
| Project/Area Number |
09450251
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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 | 一般 |
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| Research Field |
Composite materials/Physical properties
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| Research Institution | Osaka University |
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Principal Investigator |
SUGANUMA Katsuaki ISIR,Osaka University Professor, 産業科学研究所, 教授 (10154444)
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| Co-Investigator(Kenkyū-buntansha) |
INOUE Masahiro ISIR,Osaka University Research Associate, 産業科学研究所, 助手 (60291449)
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| Project Period (FY) |
1997 – 1998
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| Keywords | Metal / Ceramic composites / Processing / Interface / Mechanical properties / Thermal properties |
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| Research Abstract |
For short fiber reinforced aluminum matrix composites, preforms are first made in the process of the squeeze casting. Silica has been widely used as the sintering binder for preforms. However, silica reacts with aluminum liquid severely and causes primarily two serious problems. One is trapping active elements such as magnesium resulting in softening a matrix. The other is formation of silicon large particles in a matrix resulting in making a composite very brittle. In the present work, a new binding method of fibers and particles has been developed without silica. Fine gamma phase alumina particles is proved to be very much effective to sinter alumina fiber preforms. The strength of the preform is more than ten times higher than those sintered with silica. This makes composites deformation free and cracking free during squeeze casting. There is no problem of the magnesium trapping and the silicon particle formation. This strong skeleton structure of the fiber preform provides excellent high temperature strength to the aluminum matrix composite.
Without silica binding, silicon carbide particles/aluminum composites can be fabricated successfully. The composites with silica exhibit quite low thermal expansion much lower than the composites with silica and also lower than the values expected from theory, which is also attributed to the formation of the skeleton structure of silicon carbide particles in a composite. This composite is expected to establish as the new type of heat-sinks for electronics applications.
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