Weight
With a density of 2.7 g/cm3, aluminium is approximately one third as dense as steel.
Strength
Aluminium alloys commonly have tensile strengths of between 70 and 700 Mpa. The range for alloys used in extrusion is 150-300 Mpa. Unlike most steel grades, aluminium does not become brittle at low temperatures. Instead, it strength increases. At high temperatures, aluminium’s strength decreases. At temperatures continuously above 100°C, strength is affected to the extent that the weakening must be taken into account.
Linear expansion
Compared with other metals, aluminium has a relatively large coefficient of linear expansion. This must to be taken into account in some designs.
Malleability
Aluminium’s superior malleability is essential for extrusion. With the metal either hot or cold, this property is also exploited in the rolling of strips and foils, as well as in bending and other forming operations.
Machining
Aluminium is easily worked using most machining methods – milling, drilling, cutting, punching and bending. The energy input during machining is low. Aluminium is easy to machine using most machining methods.
Joining
Features facilitating easy jointing are often incorporated into profile design. Welding (fusion welding, friction stir welding), bonding and taping are also used for jointing.
Conductivity
Aluminium is an excellent conductor of heat and electricity. An aluminium conductor weighs approximately half as much as a copper conductor having the same conductivity.
Reflectivity
Aluminium is a good reflector of both visible light and radiated heat.
Screening EMC
Tight aluminium boxes can effectively exclude or screen electromagnetic radiation. The better the conductivity of a material, the better the shielding qualities.
Corrosion resistance
Aluminium reacts with the oxygen in the air to form an extremely thin layer of oxide. Though it is only some hundredths of an µm thick (1 µm is one thousandth of a millimetre), this layer is dense and provides excellent corrosion protection. The layer is self-repairing if damaged. Anodising increases the thickness of the oxide layer and thus improves the strength of the natural corrosion protection. Aluminium is extremely durable in neutral and slightly acid environments. In environments characterised by high or low pH values, corrosion is rapid.
Anodising increases the thickness of the oxide layer and thus improves the strength of the natural corrosion protection. Where aluminium is used outdoors, thicknesses of between 15 and 25 ¥ìm (depending on wear and risk of corrosion) are common.
Aluminium is extremely durable in neutral and slightly acid environments.
In environments characterised by high acidity or high basicity, corrosion is rapid.