Since version 9.0.1 all discs including aluminum discs were removed, hammering is no longer needed.
An aluminum disc is one of the base ingredients for crafting Poké Balls. It has the same function as an iron disc; the only difference is that it is made from aluminum ingots instead of iron ingots. An aluminum disc can be made into an aluminum base by using it with a hammer and an anvil.
|Aluminum Disc||Aluminum Ingot|