Aluminium alloys are alloys in which aluminium is the main metal used. It is usually alloyed with elements like copper, magnesium, manganese, silicon, tin and zinc. Aluminium alloys are classified into casting alloys and wrought alloys. About 85% of aluminium is used for wrought products. Cast aluminium alloys give cheap products because of their low melting point. Aluminium alloys are widely used in engineering structures.