Aluminum Alloy is used for large rovers, medium shuttles, and a whole list of other important machinery that you need on your astroneer journey. The great thing is, it isn't hard to make, and all materials are found on the starting planet!
Laterite (Aluminum)
The first thing you will need is laterite. Laterite can be found in the caves.
Once you get some laterite, head back to your base and smelt it to make aluminum.
Malichite (Copper)
The next material you need is malachite. This can be found in the rocky grey mountains on the starting planet.
Once again, you will want to smelt it to make copper.
Make Aluminum Alloy
Lastly, place the items on your chemistry lab and hit the start button!
Once it's done, you will have aluminum alloy!