An aluminium alloy is a material with metallic properties, comprising two or more chemical elements in which aluminium predominates. The alloys are obtained by adding pure aluminium, and, in its liquid state, a proportion of one or more metals which are mixed with this over several stages, carried out in ovens at temperatures which are about 720°C, the mixture is poured into moulds and is controllably cooled until it's solidification causing among other, billets for extrusion.

The metal alloys, associating one or more metals to aluminium, aim to improve its the properties according to the application it will have.

A major advantage of aluminium alloys is the possibility to obtain a wide variety of mechanical properties by thermal or mechanical treatments.

Examples of elements associated with the aluminium are:

• Copper, which favours thermal conductivity and also increases its tensile and corrosion resistance;
• Magnesium, which enhances the hardness and corrosion resistance of aluminium, favouring also its ability to welding;
• Silicon, which gives the possibility to obtain heat treatment to improve the hardness of aluminium and, when combined with magnesium, improves the corrosion resistance.

Some of the most commonly used alloys for industrial applications are: