1988 Fiscal Year Final Research Report Summary
Al-Li P/M materials with dispersion of ceramic or intermetallic compound particles
| Project/Area Number |
62550529
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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 | Nihon University |
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Principal Investigator |
KANEKO Junichi College of Industrial Technology, Nihon University, 生産工学部, 教授 (00120410)
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| Co-Investigator(Kenkyū-buntansha) |
SUGAMATA Makoto College of Industrial Technology, Nihon University, 生産工学部, 助教授 (90059600)
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| Project Period (FY) |
1987 – 1988
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| Keywords | Al-Li alloy / Powder metallurgy / Mechanical alloying / Age hardening / Dispersion strengthening / 粒子分散複合材料 / セラミックス粒子 |
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| Research Abstract |
Dispersion of ceramic particles has been studied in Al-Li alloys by applying mechanical alloying process which enables to produce alloys that are difficult or impossible to obtain by conventional melting and casting techniques. The matrix alloys used were Al-2.5Li and Al-2.5Li-1.2Cu-0.7Mg, and ceramic particles of AL_2O3, TiC and A6_4C_3 were added by the amount of 2 or 6 vo1%. P/M materials were produced from mechanically alloyed powders by cold pressing and hot extrusion. processing was all done in an argon atmoshpere so as to minimize oxidation loss of active Lithium. Metallography, tensile testing and age-hardening behavior were examined on obtained P/M materials.
Fine and uniform dispersion of ceramic particles in the matrix of Al-Li alloys was attained by mechanical alloying. Obtained P/M materials showed high hardness due to despersion strengthening. However, age hardening was remarkably suppressed probably due to increased heterogeneous precipitation sites such as dislocation, subboundary and interphase boundary. This is not peculiar to P/M materials containing Li, since the same behavior was observed in Al-Cu and Al-CuMg P/M materials processed from mechanically alloyed powder. Nonetheless, these P/M materials showed high strength due to fine dispersion of ceramic particles. Al-Li-Cu-Mg P/M alloy with dispersion of 2 vo1% TiC or AL_2O_3 showed tensile strength as high as 600 MPa in as extruded condition. Further increase of ceramic addition caused decrease of elongation and thus tensile strength. These brittle P/M materials behave more like ceramics rather than metals, since they showed lower tensile strength than the converted values from their hardness. Specific elastic modulus was as high as 30 GPa and specific strength as high as 225 MPa, much higher than those of 7075-T6.
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