Could we all soon be riding bikes made from a new form of magnesium that’s exceptionally strong and lightweight?
A team from UCLA (University of California, Los Angeles) has produced a very strong new material with an extremely high stiffness-to-weight ratio by infusing magnesium with silicon carbide nanoparticles, according to an article in Nature.
Magnesium is an abundant lightweight metal with a density about two-thirds that of aluminium. The trouble is that the magnesium alloys currently available lack the strength of other structural metals.
“Conventional synthesis and processing methods (alloying and thermomechanical processing) have reached certain limits in further improving the properties of magnesium and other metals,” says the UCLA team led by Xiao-Chun Li.
“Ceramic particles have been introduced into metal matrices to improve the strength of the metals, but unfortunately ceramic microparticles severely degrade the plasticity and machinability of metals, and nanoparticles, although they have the potential to improve strength while maintaining or even improving the plasticity of metals, are difficult to disperse uniformly in metal matrices.
“A dense uniform dispersion of silicon carbide nanoparticles (14 per cent by volume) in magnesium can be achieved through a nanoparticle self-stabilisation mechanism in molten metal. An enhancement of strength, stiffness, plasticity and high-temperature stability is simultaneously achieved, delivering a higher specific yield strength and higher specific modulus than almost all structural metals.
The new metal – actually a metal nanocomposite – has a very high specific strength and specific modulus – its strength-to-weight ratio. It has the potential to make lighter aircraft, spacecraft and cars, and perhaps has a future in the bicycle market too, although nobody yet knows the production costs.
Magnesium bikes are nothing new. The UK’s Kirk Precision started making magnesium frames back in the 1980s. These were cast in one piece rather than composed of jointed tubes.
Several other manufacturers have made magnesium bikes in the past too, including Pinarello and Merida. However, none of them have had access to this new material.
“The results we obtained so far are just scratching the surface of the hidden treasure for a new class of metals with revolutionary properties and functionalities,” said Xiao-Chun Li.
Could this herald a new age of high-end metal bikes? We'll be watching developments closely.
Mat has worked for loads of bike magazines over 20+ years, and been editor of 220 Triathlon and Cycling Plus. He's been road.cc technical editor for eight years, testing bikes, fettling the latest kit, and trying out the most up-to-the-minute clothing. We send him off around the world to get all the news from launches and shows too. He has won his category in Ironman UK 70.3 and finished on the podium in both marathons he has run. Mat is a Cambridge graduate who did a post-grad in magazine journalism, and he is a past winner of the Cycling Media Award for Specialist Online Writer.