Aluminium alloy products having a pre-sintered density of at least 90% theoretical, and methods of making such alloy products
First Claim
1. A metal powder source material for making an aluminium-based sintered product compactable to a pre-sintered density of at least 90% of theoretical by a powder metallurgy route, comprising a mixture of first, second and third aluminium-containing powders mixed with a sintering aid comprising a fourth powder comprising zinc or a zinc based alloy;
- wherein the first powder is of a hypereutectic aluminum-silicon-copper-magnesium alloy, the second powder is of a near-eutectic aluminium-silicon alloy containing from 9 to 13 wt % silicon, and the third powder is of aluminium;
the first and second powders are present in relative proportions to one another lying in the range 35;
65 wt % to 65;
35 wt %;
the third powder is present in a proportion of 5 wt % up to 35 wt % of the total weight of the three said aluminum-containing powders;
the fourth powder is present as at least 0.5 wt % of the total metal and alloy powder mixture; and
at least the first and second aluminium-containing powders have been produced by an atomizing step and not subsequently annealed.
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Abstract
Aluminium-silicon powder mixtures comprising a hypereutectic Al—Si powder, a near eutectic Al—Si powder, and a third powder which is aluminium or a hypoeutectic aluminium alloy containing alloying constituents other than silicon and less than 9 wt % silicon, with a sintering aid comprising a fourth, zinc-containing powder, are pressed and sintered to provide powder metallurgy products suitable for automotive component use in particular. The third powder in the composition permits such Al—Si powder mixtures to be compressed to a density approaching that obtained by use of an annealed powder mixture, but without the annealing step.
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Citations
16 Claims
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1. A metal powder source material for making an aluminium-based sintered product compactable to a pre-sintered density of at least 90% of theoretical by a powder metallurgy route, comprising a mixture of first, second and third aluminium-containing powders mixed with a sintering aid comprising a fourth powder comprising zinc or a zinc based alloy;
- wherein the first powder is of a hypereutectic aluminum-silicon-copper-magnesium alloy, the second powder is of a near-eutectic aluminium-silicon alloy containing from 9 to 13 wt % silicon, and the third powder is of aluminium;
the first and second powders are present in relative proportions to one another lying in the range 35;
65 wt % to 65;
35 wt %;
the third powder is present in a proportion of 5 wt % up to 35 wt % of the total weight of the three said aluminum-containing powders;
the fourth powder is present as at least 0.5 wt % of the total metal and alloy powder mixture; and
at least the first and second aluminium-containing powders have been produced by an atomizing step and not subsequently annealed. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
- wherein the first powder is of a hypereutectic aluminum-silicon-copper-magnesium alloy, the second powder is of a near-eutectic aluminium-silicon alloy containing from 9 to 13 wt % silicon, and the third powder is of aluminium;
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9. A metal powder source material for making an aluminium-based sintered product compactable to a pre-sintered density of at least 90% of theoretical by a powder metallurgy route, comprising a mixture of first, second and third aluminium-containing powders mixed with a sintering aid comprising a fourth powder comprising zinc or a zinc based alloy;
- wherein the first powder is of a hypereutectic aluminum-silicon-copper-magnesium alloy, the second powder is of a near-eutectic aluminium-silicon alloy containing from 9 to 13 wt % silicon, and the third powder is of a hypoeutectic aluminium alloy containing alloying constituents other than silicon and from 0.3 wt % to less than 0.6 wt % silicon;
the first and second powders are present in relative proportions to one another lying in the range 35;
65 wt % to 65;
35 wt %;
the third powder is present in a proportion of 5 wt % up to 35 wt % of the total weight of the three said aluminium-containing powders;
the fourth powder is present as at least 0.5 wt % of the total metal and alloy powder mixture;
wherein at least the first and second aluminium-containing powders have been produced by an atomizing step and not subsequently annealed. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
- wherein the first powder is of a hypereutectic aluminum-silicon-copper-magnesium alloy, the second powder is of a near-eutectic aluminium-silicon alloy containing from 9 to 13 wt % silicon, and the third powder is of a hypoeutectic aluminium alloy containing alloying constituents other than silicon and from 0.3 wt % to less than 0.6 wt % silicon;
Specification