Engineering malleable Mg for your MG Tuesday, 07 November 2017

Due to its brittle nature, magnesium is not widely used in the manufacture of vehicles, but thanks to Australian engineers that may all be about to change.

An engineering team at Monash University has discovered a way to shape pure magnesium at room temperature which could have major implications for the transport industry. Usually magnesium is formed at temperatures between 200 and 400 Celsius and, up until now, most magnesium components in the auto industry are made using castings for steering wheels and casings.

In what is being dubbed a “world-first”, the team, led by Professor Nick Birbilis from the Department of Materials Science and Engineering, has found a way to change the microstructure of magnesium. The change from a brittle microstructure to one that is malleable or superformable could see it used for car panels.

Professor Birbilis’ team chose to work with magnesium because it is the lightest structural metal; its density is two-thirds that of aluminium and a quarter of steel. Consequently magnesium could be used to replace heavier alloys presently used in making cars, which could result in lighter vehicles, leading to better fuel economy and lesser emissions.

Team member Dr Randy (Zhuoran) Zeng said with the technique, magnesium can now be rolled, bent or compressed into any shape - even at room temperature.

“By refining the microstructure we have changed the deformation mechanism from intra-granular (brittle) to inter-granular (formable),” Dr Zeng said.

“We can even roll it to the thickness of aluminium foil and bend it 180 degrees after rolling.”

And it doesn’t crack. The process involves pushing pure magnesium through a die at 80 degrees Celsius, then it is cold-rolled. It can be cold-rolled at room temperature to under one millimetre in thickness without cracking. This new technique is set to reduce energy costs associated with heating magnesium.

The Monash engineering team has published its research in the Nature Communications journal where you can read the full paper.