By adding small quantities of elements such as lead to certain materials, scientists at the University of Wisconsin-Madison have discovered they can make a more versatile aluminium alloy that’s stronger by weight than steel.
The alloy’s strength is said to originate from the effect of almost countless numbers of tiny, pure aluminium particles (nanocrystals) dispersed uniformly throughout the material’s otherwise random, or amorphous, atomic structure.
A miniature internal framework, the aluminium nanocrystals act as strengtheners by blocking the paths along which the amorphous alloy traditionally deforms.
The key is to produce and control the number and location of the nanocrystals, said John Perepezko, materials science and engineering professor who conducted the research with former graduate students Don Allen and James Foley. ‘What we found is that by adding tiny ‘seeds,’ such as lead particles, each particle acted as a little catalyst and produced an aluminium nanocrystal,’ he said.
The strategy can also apply to other materials. For example, in iron-based alloys used for electronics applications, the lead nucleates nanocrystals, which enhances the material’s magnetic properties rather than it’s strength.
The new materials, which manufacturers can also make in bulk form, could be used in everything from golf clubs and bicycles to transformers, aeroplane parts or other high-performance applications.