Properties of Aluminium

1. Weight

The specific gravity of aluminium is 2.7, about one-third that of iron (7.9) and copper (8.9). The weight to strength ratio of aluminium makes it an ideal construction material for the transport industry – air, sea, road and rail – where its light weight contributes to energy saving, increased load capacity and speed. Aluminium is also used in large scale construction of high-rise buildings, power transmission cables, and towers.

2. Corrosion resistance

The specific gravity of aluminium is 2.7, about one-third that of iron (7.9) and copper (8.9). The weight to strength ratio of aluminium makes it an ideal construction material for the transport industry – air, sea, road and rail – where its light weight contributes to energy saving, increased load capacity and speed. Aluminium is also used in large scale construction of high-rise buildings, power transmission cables, and towers.

3. Machinability

Aluminium can be easily fabricated into casts or forged shapes, foil, sheet, rod, tube, and wire. It also displays excellent machinability and plasticity in bending, cutting, and drawing. Aluminium is considered to be the best material for complex-sectioned hollow extrusion.

4. Strength

The tensile strength of pure aluminium is not high, but depending upon the alloy or temper, a strength of up to 60 kg/mm2 can be achieved. You can choose the alloy with the most suitable strength characteristics you need according to your application. Some alloys are stronger than ordinary steel or even equal to special (alloy and treated) steels in tensile strength. While steel becomes brittle at low temperatures aluminium increases in tensile strength. Because of its low modulus of elasticity, aluminium absorbs impact and is used in potentially high-impact applications such as automobile bumpers.

5. Expansion

Aluminium extrusions have a comparatively high coefficient of expansion which is 0.000023mm per mm length of extrusion per °C. A length of aluminium extrusion 6m long will expand over 4mm when the temperature rises 30°C. When designing, especially building design, provision should be made for expansion and contraction caused by temperature changes. Thermal expansion is particularly important where aluminium extrusions are used with other materials having different expansion rate.

6. Surface enhancement

Aluminium can be chemically and electrochemically surface treated, painted or powder-coated for enhanced protection and appearance. A wide range of colours is available. Aluminium is thus widely used for interior and exterior cladding of buildings and vehicles, and the fabrication of household and commercial appliances.

7. Electrical conduction

The electrical conductivity of aluminium is approximately 60% of copper yet about one-third the weight. Aluminium is a very economical material as an electric conductor and is widely utilized in power-transmission cables, bases of electric bulbs and in other electric applications.

8. Heat conduction

Aluminium is about three times as thermo-conductive as steel. It is used for cooking utensils, air-conditioners, industrial heat exchangers, automobile engine parts and solar energy collectors.

9. Magnetic sensitivity

Aluminium is non-magnetic and is used where the use of magnetic materials would be detrimental to equipment performance, such as in the construction of compasses, parabolic antennae, computer disks and other magnetically driven applications.

10. Reflectivity

The surface of uncoated aluminium is highly reflective of light, radiant heat and electronic waves – the purer the metal the more so. This feature is utilised in mirrors and reflectors for stoves, infrared dryers, lighting equipment, light-wave-guides and in building temperature control.

11. Recyclablity

Owing to its low melting temperature, aluminium is economically recyclable, requiring only about 3.5% the energy required for smelting. Use of recycled aluminium has benefits for all concerned with conservation of energy and natural resources.