Qualified Rapid Products (QRP), and end-to-end additive manufacturing service provider, has added Elementum 3D’s Aluminum 6061-RAM2 to its line of available materials.
3D printing in aluminum is common, but it is typically carried out using an alloy with high silicon content, namely AlSi10. The aerospace industry often requires 6061 aluminum, which is very strong and common for their parts. AlSi10 has material properties similar to most aluminum alloys, acting more like a casting alloy, but 6061 is on the higher end of aluminum alloys.
Normally 6061 doesn’t weld well because it results in little cracks behind the weld bead where it cools too quickly. However, metal powder supplier Elementum 3D has made slight changes to the chemical composition to make it print well. At QRP is even prints better than the typical AlSi10 that the industry is used to. Elementum 3D’s datasheet shows material properties very similar to wrought 6061.
Learning to fly with Aluminum 6061
In the latest Aluminum Opportunities in Additive Manufacturing – 2018 report from SmarTech Publishing, Aluminum 6061 was identified as a key alloy for AM production, especially in aerospace. As the report highlighted, 6061 alloys are now increasingly processed with metal laser powder bed fusion processes and are able to match the performance of the conventionally produced materials. There has also been some recent success reported with 7075 but research is ongoing.
The aerospace industry works with 6061 aluminum. It has good corrosion resistance and finishing ability and has good thermal conductivity. The strength of the T6 temper (The T6 cycle is the standard heat treatment procedure for this alloy: solution treatment followed by artificial aging) is similar to that of mild steel. It is stronger than the more commonly used silicon blend (AlSi10) but results in a rougher surface when 3D printed. The resulting thermal conductivity is comparable. Notably, Elementum 3D says the surface roughness of its Aluminum 6061-RAM2 material is actually better than AlSi10.
There are a number of powder suppliers who sell aluminum 6061 for AM with different levels of quality. Most print service providers today don’t offer it because it takes time to develop parameters for it and most adopters are used to AlSi10 and like how it looks. AM parts can be heat treated like any other 6061 aluminum, although strong supports are needed to control the warpage you would see through the precipitation phase (quenching). Atomized aluminum 6061 powder is widely available and can be purchased for as low as $25/kg. Though, as Elementum 3D specifies, the price of powder that meets the size, shape and quality requirements for LPBF processes can be significantly higher.