当前申请(专利权)人地址：
127 Industry Boulevard,North Huntingdon, PA 15642,US
发明人：
DOUGHERTY, PATRICK | WILHELMY, DEBORAH M. | MYERS, KYLE
摘要：
A process for producing a high density aluminum alloy part from a green part like those produced by binder jet additive manufacturing is described. The process utilizes a build powder that includes a densification aid mixed with the aluminum alloy powder and gets incorporated into the green part during the printing process. Certain embodiments include a continuous high flow of nitrogen gas and controlled heating of the green part and provides a high density aluminum alloy part exhibiting densities of 95% or greater.
权利要求：
CLAIMS
What is claimed is:
1. A method for producing a densified aluminum part, comprising the steps of: forming a green part from build powder and a binder wherein the green part comprises less than 5% by weight of the binder, and wherein the build powder comprises: aluminum alloy powder comprising aluminum alloy particles and having an aluminum alloy composition comprising a magnesium content ranging from about 0.5 to about 5 weight % of the aluminum alloy composition; and a densification aid mixed with the aluminum alloy powder in an amount ranging from about 0.1 to about 3.0 weight % of the build powder, wherein the densification aid has an average particle size that is smaller than the aluminum alloy particles; and densifying the green part by heating the green part under a continuous flow of nitrogen gas of at least 5 SCFH and to a sintering temperature between the solidus and liquid temperature of the aluminum alloy sufficient to promote reaction-assisted super-solidus liquid phase sintering, wherein the densified aluminum part has a density of at least 95%.
2. The method of claim 1, wherein the aluminum alloy is a 6XXX series alloy.
3. The method of claim 1, wherein the aluminum alloy is 6061.
4. The method of claim 1, wherein the aluminum alloy powder has an average particle size in the range from about 20 microns to about 75 microns.
5. The method of claim 1, wherein the densification aid is selected from the group consisting of tin, magnesium, copper, silver, and combinations thereof.
6. The method of claim 1, wherein the densification aid is tin.
7. The method of claim 1, wherein the sintering temperature ranges from about 610C to about 660C.
9. The method of claim 1, wherein the continuous flow of nitrogen ranges from about 5 SCFH to about 40 SCFH.
10. The method of claim 1, wherein the forming step is performed by binder jet additive manufacturing.
11. The method of claim 1, wherein the aluminum alloy is 6061, the densification aid comprises tin in an amount ranging from about 0.1 to about 0.5% by weight of the build powder, and the continuous nitrogen flow is at least 20 SCFH.
12. The method of claim 1, wherein the densified aluminum part has a density of at least 97%.
13. The method of claim 1, wherein the densified aluminum part has a density of at least 99%.
14. The method of claim 1, wherein the density of the green part is in a range of about 50% to about 65%.
15. The method of claim 1, wherein the average particle size of the densification aid is sized to substantially reside in interstitial spaces of the aluminum alloy powder.
16. The method of claim 1, wherein the average particle size of the densification ais sized to wholly reside in interstitial spaces of the aluminum alloy powder.
17. A method for producing an aluminum part, comprising the steps of: forming a green part by binder jet additive manufacturing from build powder and a binder wherein the green part has a binder content of less than 5% by weight and a density in the range of about 50% to about 65%, and wherein the build powder comprises: an aluminum 6061 alloy powder comprising aluminum 6061 alloy particles and having an aluminum alloy composition comprising a magnesium content ranging from about 0.5 to about 2 weight% of the aluminum alloy composition; and
a densification aid selected from the group consisting of tin, magnesium, copper, and silver mixed with the aluminum alloy powder in an amount ranging from about 0.1 to about 3.0 weight% of the build powder, wherein the densification aid has an average particle size that is sized to substantially reside in interstitial spaces of the aluminum alloy powder; and densifying the green part by heating the green part under a continuous flow of nitrogen gas of at least 20 SCFH and to a temperature between the solidus and liquid temperature of the aluminum alloy sufficient to promote reaction-assisted super-solidus liquid phase sintering, wherein the aluminum part has a density of at least 95%.
18. The method of claim 17, wherein the aluminum part has a density of at least 97%.
19. The method of claim 17, wherein the densification aid is tin in an amount ranging from about 0.1 to about 0.5 weight% of the build powder.
20. The method of claim 17, wherein the aluminum 6061 alloy particles have an average particle size ranging from about 20 microns to about 75 microns.
21. The method of claim 17, wherein the densification aid has an average particle size that is sized to wholly reside in interstitial spaces of the aluminum alloy powder.
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