When aluminium alloys were first commercialized at the end of the nineteenth century they were a new and aspirational material. Used for applications such as cutlery and dinnerware, aluminium was seen as having greater status even than gold and was around twice the cost. In the 1950s aluminium went through another period of promotion, when its light weight and strength were applied to buildings and iconic vehicles such as the Airstream caravan. Like plastic, which has followed a similarly progressive series of interpretations and associations, aluminium still maintains its value as a material but with embedded aspirational values and, together with magnesium and titanium, is a part of the trio of lightweight metals. It’s lightweight qualities were exploited in its use as the material for the 2012 Olympic torches.
In little over a century, this relatively new addition to the family of metals has become one of the world’s most widely used metals, second only to steel. With its winning combination of strength, low weight and resistance to corrosion, aluminium has become the optimum metal for all kinds of transportation applications, including ocean liners, aircrafts and even spaceships. When ground into a powder form, aluminium is one of the few metals that retains a shiny appearance, which is why it is commonly found in paints and plastics, where it is used to produce a metallic effect. Aluminium is 100 per cent recyclable, and nearly three-quarters of all aluminium ever made remains in use today!
Image: Olympic Torch, Barber Osgerby
Key features
•Good strength-to-weight ratio
•Low cost
•Versatile processing
•Non magnetic
•Achieves a high polish
•Excellent corrosion resistance
•Good machinability
•Melts at 660ºC (1220ºF)
•Recyclable
Sources
Bauxite, the ore from which aluminium is extracted, occurs mainly in tropical and sub-tropical areas – Africa, West Indies, South America and Australia – with some deposits in Europe.
Cost
£1.28 ($2) per kg.
Sustainability issues
Producing aluminium is very energy intensive to process and as a result is extensively recycled due to the low energy needed to recycle it in comparison to extracting it from its ore. Recycling provides an energy saving of 95% over the use of the primary metal. The low weight and corrosion resilience of aluminium provides savings in weight and also in extending product life.
Production
Aluminium can just as easily be formed for one-off production as it can for batch and mass production. Processing methods include extrusion, various forms of casting, machining and impact extrusion.
Typical applications
With a material that is so prolific it is impossible to describe its ‘typical’ applications because there are so many. They range from the ultra-precise, machined mid-section wings of the biggest commercial airliner in the world, the Airbus A380, down to a ring-pull on a fizzy drinks can.
Derivatives
–Metpreg (aluminium with glass fibres)
–Nambe in the US produce various proprietary grades of aluminium in their range of designed products
–Duralumin (copper and aluminium alloy)
–Magnalium (aluminium and magnesium)
–Silumin (aluminium and silicon)
–Zamak (zinc, aluminium, magnesium and copper)
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–Easy to processes –Versatile –Good strength-to-weight ratio –Corrosion resistant –Recyclable |
–Extremely energy intensive to produce |