Monash engineering researchers co-discover ultralight magnesium alloy

Professor Nick Birbilis, Head of Materials Science and Engineering Department at Monash Engineering School, said that the new magnesium-lithium alloy weighs about half as much as already lightweight aluminum, and could potentially be used across a broad range of manufacturing to reduce the weight of motor vehicles and other items such as laptops by up to 40 per cent.

Professor Birbilis, who is part of a research team that includes Professor Michael Ferry and key researcher Dr Wanqiang Xu from University of New South Wales, came across the discovery by chance when they noticed that a piece of the magnesium alloy had been resting in a beaker of water for quite some time without corroding.
“Normally for magnesium alloys, you walk away and a day later you come back and there’s very little left. This particular alloy stunned everyone in that it looked pristine after very lengthy periods of exposure in saltwater conditions,” he said.
The findings, published in the current edition of Nature Materials, describe how the alloy forms a protective layer of carbonate-rich film upon atmospheric exposure, making it immune to corrosion when tested in laboratory settings.
Even when scratched, the metal is able to reform a protective surface film, making it similar to stainless steel, but at a fraction of the weight. In fact, this magnesium alloy could be the world’s lightest and strongest metal.
This discovery is particularly relevant to the transport industry, where a reduction in the weight of cars, trucks and airoplanes could improve fuel efficiency and greatly reduce greenhouse gas emissions.
“These panels will make many vehicles and consumer products much lighter and, eventually, just as durable as today’s corrosion-resistant materials, another example of how advanced manufacturing is unlocking the potential of materials that have been under investigation—in too narrow a manner—for centuries,” said Professor Birbilis.
The international team working on this project including researchers from Monash University and UNSW, Nanjing University of Technology and Chinese aluminum-production giant, CHALCO, also used facilities at the Australian Synchrotron to study the molecular composition of the alloy and carbonate-rich film.
Prof Birbilis said they hope to better understand how the corrosion process is averted and are working toward imparting the ‘stainless’ effect to a wider range of alloys. This is being further assisted by an ARC Discovery Project awarded this year.

Department of Materials Science and Engineering

The ability to understand and manipulate materials and their properties is a key factor in any industrial process or technology, new or old. Increasingly nanotechnology, sustainable materials and biomaterials are becoming important areas of endeavor. Because of the enabling aspect of Materials Science and Engineering, and the multidisciplinary nature of the skills learned, Monash Engineering graduates are much in demand in many industrial organisations. Many also go into research, be it in academia, industrial laboratories or government research organisations.
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