I am pretty well familiar with ferrous metallurgy. I understand pretty well how to heat treat steel to get soft, tough, or hard states. But aluminum…about two years ago I forged some parts for a neighbor from some extrusion grade aluminum I had laying around ( 2024 I think) the stuff forged beautifully. It moved like copper and working down two inch material meant I got to play with for a bit. Now machining was not the same story. The parts had to finish with a 1/2-13 thread. The stuff cut like cold peanut butter. It was soft- too soft. Material would tear out, deform, chips welding back to the parts causing big halls to form. I know there are alloys for different applications. I just obtained a mig welder for aluminum. A pulse mig set up for aluminum. Playing with it, the idea of branching into aluminum fence occurs to me, but I don’t know which variety would be best for this kind of fabricating. Is there a good book on this anyone can recommend?

See if you can get a copy of ASM metals reference book.