Method for preparation of sintered parts from an aluminum sinter mixture
First Claim
1. A process for producing sintered parts from an aluminum sintering mixture comprising the following steps:
- mixing between 10 and 70% by weight of a pure aluminum power and between 30 and 90% by weight of an aluminum alloy powder to form an aluminum sintering mixture;
mixing the aluminum sintering mixture with between 0.5% and 2% by weight of a compacting additive to form a mix;
compacting the mix to form a green preform; and
sintering the green preform;
wherein the aluminum alloy powder comprises;
aluminum, between 14 and 35% by weight of Si, between 1.0 and 7% by weight of Cu, between 0.3 and 2.5% by weight of Mg, between 0.03 and 6% by weight of one or more elements selected from the group consisting of Ti, Fe, V, Zr, Ni, and Cr; and
wherein the pure aluminum powder and the aluminum alloy powder have a maximum grain size of 350 μ
m.
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Abstract
Described is a process for producing sintered parts from an aluminum sintering mixture, wherein between 10 and 70% by weight of pure aluminum powder and between 30 and 90% by weight of an aluminum alloy powder are mixed to form an aluminum sintering mixture. The aluminum alloy powder is of the following composition:
between 14 and 35% by weight of Si;
between 1 and 7% by weight of Cu;
between 0.3 and 2.5% by weight of Mg;
between 0.3 and 6% by weight of a transition metal, the balance aluminum.
The pure alloy powder and the aluminum alloy powder are each of a grain size of a maximum of 315 μm. The aluminum sintering mixture is mixed with between 0.5 and 2% by weight of compacting additive. The mix of alloy sintering mixture and compacting additive is compacted to form a green compact. The green compact is then sintered. As no low-melting phases occur in the invention, sintered bodies which are stable in respect of shape are reproducibly obtained in the sintering operation.
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Citations
9 Claims
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1. A process for producing sintered parts from an aluminum sintering mixture comprising the following steps:
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mixing between 10 and 70% by weight of a pure aluminum power and between 30 and 90% by weight of an aluminum alloy powder to form an aluminum sintering mixture;
mixing the aluminum sintering mixture with between 0.5% and 2% by weight of a compacting additive to form a mix;
compacting the mix to form a green preform; and
sintering the green preform;
wherein the aluminum alloy powder comprises;
aluminum, between 14 and 35% by weight of Si, between 1.0 and 7% by weight of Cu, between 0.3 and 2.5% by weight of Mg, between 0.03 and 6% by weight of one or more elements selected from the group consisting of Ti, Fe, V, Zr, Ni, and Cr; and
wherein the pure aluminum powder and the aluminum alloy powder have a maximum grain size of 350 μ
m.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
atomizing an aluminum alloy powder melt and a pure aluminum powder melt in a protective gas environment or in air to respectively produce the aluminum alloy powder and the pure aluminum powder.
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3. A process as set forth in claim 1, further comprising the step of:
atomizing a pure aluminum powder melt in air to produce the pure aluminum powder.
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4. A process as set forth in claim 2, further comprising the step of:
quenching the aluminum alloy powder melt such that Si-primary crystallites are present in a fine distribution of a maximum of 25 μ
m, with the Si-content being above the eutectic composition.
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5. A process as set forth in claim 1, wherein the mix is compacted to 95% of a theoretical density for the green preform.
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6. A process as set forth in claim 1, wherein the sintering of the green preform is effected in a protective gas atmosphere.
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7. A process as set forth in claim 6, wherein the sintering of the green preform is effected in a pure nitrogen atmosphere with a low dew point.
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8. A process as set forth in one of the preceding claims, further comprising the step of:
dewaxing the green preform prior to the sintering.
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9. The process according to claim 1, wherein the pure aluminum powder and the aluminum alloy powder have a maximum grain size of 200 μ
- m.
Specification