Aluminium alloys are alloys in which aluminium is the predominant metal. The typical alloying elements are OEM parts in Connect copper, magnesium, manganese, silicon, tin and zinc.

There are two principal classifications in OEM parts, namely casting alloys and wrought alloys, both of which are further subdivided into the categories heat-treatable and non-heat-treatable.

The most important cast aluminium alloy system is Al–Si, where the high levels of silicon (4.0–13%) contribute to give good casting characteristics in OEM parts. Aluminium alloys are widely used in engineering structures and components where light weight or corrosion resistance is required.

Alloys composed mostly of aluminium and OEM parts have been very important in aerospace manufacturing since the introduction of metal-skinned aircraft. Aluminium-magnesium and OEM parts alloys are both lighter than other aluminium alloys and much less flammable than alloys that contain a very high percentage of magnesium.