Metallurgy: 2219/2319 versus 6061

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I'm looking at an automotive application (namely cylinder heads).  To me it looks like 2219/2319 is actually better than 6061 (in a T6 heat treat state) but is obviously much more expensive.  Is there something I'm missing in the datasheets, or would this be the case?Specifically, I'm looking at an application where the 2319 would be used to build up material.Thoughts?  I'm not sure if I can get finite element analysis run but I am building the CAD of the part now.Outrunning my headlights since '81.
Reply:The 2219 alloy is an aluminum-copper alloy that has higher strength in the heat treated condition but lower ductility, meaning it will not deform as much as 6061-T6 before fracture. Also, 2219 has lower corrosion resistance and lower weldability than 6061. In fact, in many applications, 2219 is plated with a more pure Al alloy such as a 10XX series alloy to increase corrosion resistance. If you need to weld this material, I would not choose a 2219 alloy, due to the difficulty in welding and the typical need for post weld heat treatment.  2219/2319 are more expensive due to the relatively high Cu content at approximately 6%. If you chose this alloy, the primary benefit I see is the superior strength at elevated temperatures.
Reply:Thank you very much for that rundown - that's about what I got from it.  Is machineability of the 2 series good?  When you say corrosion, do you mean it will get a frosty look to it?  I don't think that will be an issue, but with water flowing through it at temperature there could be longevity issues?This would be electron beam additive manufacturing, meaning they take 2319 weld filler and an electron beam in a vacuum chamber to 3D print a piece, so it shouldn't need to be welded afterwards at all, but basically every critical tolerance will need to be machined.  Consider it a billet without all the machining cost and trouble of locating water passages that you get with billets.Bottom line is casting just isn't economical for the small number of these that can get sold and with this process the deposition rates may well be high enough that even after machining it will be significantly cheaper than billets.Outrunning my headlights since '81.