The aerospace industry loves to work with 6061 aluminum. It has good corrosion resistance and finishing ability and has good thermal conductivity. The strength of the T6 temper is similar to that of mild steel. So I hear a lot of clients, especially aerospace clients just exploring additive manufacturing, ask if we can print in 6061.
Most aluminum parts made with additive manufacturing (often called DMLS although that trade name is inaccurate) are made with a silicon blend (AlSi10) that has properties similar to an A356 casting alloy. The silicon helps it wet nicely in the welding process and results in a smoother surface. The resulting thermal conductivity is between 120 and 180 W/m-Kwhich is comparable to that of 6061– maybe a bit lower.
However, you can 3D print in 6061 aluminum and there are a number of powder suppliers who sell it with different levels of quality. A lot of print service providers don’t print in it because it takes time to develop parameters for it and people are starting to get used to the AlSi10 and like how it looks. You could heat treat these parts just like you can any other 6061 aluminum although you will need to plan on strong supports to control the warpage you would see through the precipitation phase (quenching).
6061 welded together surprisingly well although the surface roughness was noticeably worse. It also had more internal stresses in it requiring stronger supports. We played with our parameters a little just to get an initial print but there is a lot of room for improvement through a more detailed parameter development study. For these particular parts we didn’t try to temper them but simply stress relieved them. In all we are encouraged by the potential of using 6061 where more strength is needed. But if you don’t need those specific properties, you’ll have more supplier options, less distortion and better surface finish if you use the AlSi10.