Properties & Sustainability
Aluminium has a unique combination of properties that can be amplified and utilised through alloying. For example – substituting steel components in a motor vehicle with aluminium components can contribute to a lighter more fuel efficient vehicle, however pure aluminium is very malleable; by alloying aluminium with magnesium, manufacturers are able to create a metal that is as strong as steel at only one third of the weight.
Some of the characteristics of aluminium include:
When mixed with small amount of other metals (particularly magnesium) to create alloys, aluminium is as strong as steel.
Its combination of properties ensure aluminium and its alloys can be easily shaped by any of the main industrial metalworking processes - rolling, extrusion, forging and casting.
Aluminium has excellent barrier function which keeps out air, light and microorganisms.
Aluminium can weigh only one third of a piece of steel that is the same size and shape.
Aluminium forms a natural film on its surface upon exposure to oxygen. This film is called aluminium oxide, and it protects the surface of the aluminium. If this film is scratched or damaged, it will instantly reform. It is only under certain conditions and exposure to certain elements that aluminium will corrode.
Aluminium’s unique combination of strength and corrosion resistance makes it a particularly durable material.
Recycling aluminium does not compromise any of its unique properties, and uses only 5% of the energy used to create the original product. Aluminium can be reused endlessly – approximately two-thirds of all aluminium ever produced is still in use today – representing a growing “energy and resource bank”.
Aluminium is not adversely affected by steam sterilising and cleaning and will not harbour bacteria or insects.
Non-Magnetic and Non-Sparking
Aluminium is non-magnetic and non-sparking. These properties make it a suitable material for applications where explosive vapour mixtures are present.
Aluminium is one of two common metals with electrical conductivity high enough to permit its use as an electrical conductor – copper being the other. While aluminium’s conductivity is 62% of that of copper, its light-weight is aluminium’s main benefit – an aluminium conductor of equal current-carrying capacity is half the weight of a copper conductor.
Thermal Barrier and Conductor
Aluminium in its different applications can act as both a good barrier against and conductor of heat.
The Australian aluminium industry employs a lifecycle approach to address the challenges of climate change, focusing not only on the energy required to produce aluminium products but also on the energy savings to be made through their use and reuse.
It is in the use phase that the majority of energy is used and/or saved (e.g. during the useful life of cars, buildings, aircraft, etc).
Aluminium’s contribution to sustainable transportation
The high strength-to-weight ratio of aluminium plays a crucial role in producing lighter vehicles and other forms of transport, reducing fuel consumption without compromising performance and safety. The use of lightweight aluminium components in a vehicle can save six to twelve times the energy taken to produce the primary aluminium used in its construction. Up to eight per cent fuel savings can be realized for every 10% reduction in weight. One kilogram of aluminium, used to replace heavier materials in a car or light truck, has the potential to eliminate 20kg of CO2 over the lifetime of the vehicle. For other vehicles, such as trains, ferries and aircraft, the potential savings are even greater.
Aluminium and Jaguar: Aluminium has become an integral material in the development of Jaguar’s contemporary vehicle models, allowing the car manufacturer to realise sustainable, high performance designs. Through the application of aluminium, the new XJ weighs up to 150kg less than its class competitors – this equates to a saving of 3 tonnes of CO2 over the life of the vehicle.
The Story of Aluminium - article on the Jaguar website
All New Jaguar XJ, Aluminium Body - video
Aluminium’s contribution to sustainable building and construction
Aluminium is increasingly becoming the material of choice in modern sustainable buildings due to its corrosion resistance and recyclability.
“The energy used for primary production is embodied, to a large extent, in the metal and, consequently, in the building too. Today’s buildings and their contents therefore present large “urban mines” of around 400 million tonnes of aluminium metal that can be extracted and recycled by future generations through the use of only 5% of the originally used energy, not just once but repeatedly.
Aluminium is extensively employed in buildings, but it does not remain permanently in place. Buildings are remodeled periodically, and even deconstructed, thereby freeing the aluminium for recycling. Therefore, it is not inaccurate to regard this aluminium as “urban ore” and cities as “urban mines”.
The aluminium is embodied in such items as exterior surfaces, counters, appliances, and electronics. In highly-developed countries, aluminium in buildings of all types amounts to between 120 and 200 kg per person. Globally, it is estimated that buildings and their contents contain some 400 million tonnes of aluminium, which can be extracted and reused by future generations time after time, requiring only about 5% of the energy originally used to extract and process aluminium from more traditional geologic sources.
Aluminium recycling thus not only represents good urban housekeeping, it provides major energy benefits today and tomorrow.”
Professor Thomas E. Graedel, Yale School of Forestry and Environmental Science