Today's light-weight beverage cans are made of aluminium that is as thin as two pages of this newspaper, yet when formed into the shape of a tube can support the weight of an average adult, this month's Scientific American says. 'Produced by the hundreds of millons every day, the modern can . . . is a tribute to precision design and engineering.'
More aluminium beverage cans are produced each year than nails or paperclips - 100 billion in the US alone - yet each can withstand a pressure three times greater than a car tyre, while using almost one-third less metal than 30 years ago.
Such light-weight strength is the result of the sort of precision and attention to detail that goes into the design of an aircraft's wing, according to the metallurgists William Hosford, of the University of Michigan, and John Duncan, of Auckland University in New Zealand.
Professor Hosford and Professor Duncan describe how the evolution of the beverage can has reduced the amount of aluminium and the energy used in making each can. Can makers are aiming to reduce the weight of a can by a further 20 per cent, they say.
'Reducing the can's mass by 1 per cent will save approximately dollars 20m ( pounds 13.3m) a year in aluminium.'
Despite using less aluminium, manufacturers have increased the strength of cans by dissolving magnesium into the material, which slightly distorts the molecular structure of the metal making it better able to resist deformations.
Flattening and rolling the aluminium sheets at room temperatures prior to making a can also increases the strength of the metal, enabling manufacturers to shave a few more thousandths of a millimetre off the wall of a container.
It takes energy equivalent to a 100W light bulb being lit for six hours to make one aluminium can, the researchers say. 'One way to reduce this expense is through recycling, which can save up to 95 per cent of the energy cost.'
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