Pure aluminium contains between 99 and 99.8% of aluminium. The purer it is, the better the corrosion resistance. Pure aluminium, however, does not possess extremely good mechanical properties, resulting in the application of aluminium alloys. The best mechanical properties of aluminium are attained by adding copper, nickel, magnesium, and silicon.

Most aluminium alloys applied for milling purposes (extrusion, rolling, drawing, and forging) are alloyed with magnesium and copper. Magnesium enhances the strength of aluminium (subject to proper processing) and corrosion resistance as well as simultaneously reduces its castability, formability and conductivity. Copper enhances its strength significantly and simultaneously reduces its corrosion resistance as well. Most aluminium alloys applied for casting purposes are based on added silicon.

With regard to the metalworking industry, the quantity of manufactured light aluminium alloys is only exceeded by the quantity of manufactured steel. During recent years, global production of aluminium has been exceeding 30 million tonnes per year, an amount that exceeds the total annual production of copper, tin, and lead.