Properties of Aluminium
Aluminium has a unique and unbeatable combination of properties that make it into a versatile, highly usable and attractive construction material.
Aluminium is light with a density one third that of steel, 2.700 kg/m3.
Aluminium is strong with a tensile strength of 70 to 700 MPa depending on the alloy and manufacturing process. Extrusions of the right alloy and design are as strong as structural steel.
The Young’s modulus for aluminium is a third that of steel (E = 70,000 MPa). This means that the moment of inertia has to be three times as great for an aluminium extrusion to achieve the same deflection as a steel profile.
Aluminium has a good formability, a characteristic that is used to the full in extruding. Aluminium can also be cast, drawn and milled.
Aluminium is very easy to machine. Ordinary machining equipment can be used such as saws and drills. Aluminium is also suitable for forming in both the hot and the cold condition.
Aluminium can be joined using all the normal methods available such as welding, soldering, adhesive bonding and riveting.
A thin layer of oxide is formed in contact with air, which provides very good protection against corrosion even in corrosive environments. This layer can be further strengthened by surface treatments such as anodising or powder coating.
The thermal and electrical conductivities are very good even when compared with copper. Furthermore, an aluminium conductor has only half the weight of an equivalent copper conductor.
Aluminium has a relatively high coefficient of linear expansion compared to other metals. This should be taken into account at the design stage to compensate for differences in expansion.
Aluminium is not poisonous and is therefore highly suitable for the preparation and storage of food.
Aluminium is a good reflector of both light and heat.