When most of us think of structural metals (load-bearing), aluminum and titanium come to mind. Magnesium is another option. And for good reason. It’s two-thirds the density of aluminum and is the lightest structural metal out there. But magnesium has some drawbacks. It’s just not as stiff or strong as many of these other metals.
The idea of using nanoparticles to enhance the strength of metals isn’t a new one according to Xiaochun Li, the principal investigator on the research and Raytheon Chair in Manufacturing Engineering at UCLA. “But no groups have been able to disperse ceramic nanoparticles in molten metals until now,” says Li.
And the new method isn’t just limited to magnesium. “With an infusion of physics and materials processing, our method paves a new way to enhance the performance of many different kinds of metals by evenly infusing dense nanoparticles to enhance the performance of metals to meet energy and sustainability challenges in today’s society,” Li adds.
How the researchers did it
The biggest problem when using nanoscale ceramic particles is they tend to clump together. Getting them to disperse evenly is vital. To do this, researchers dispersed the particles into a molten magnesium-zinc alloy. This nanoparticle dispersion uses the kinetic energy in the particles’ movement according to the researchers. It spreads out evenly and prevents them from clumping.
Another technique called high-pressure torsion (compressing it) was used to make the new metal even stronger.
Li believes they “are just scratching the surface of the hidden treasure for a new class of metals with revolutionary properties and functionalities.”
The new magnesium metal
You can see a deformed sample of pure metal on the left. On the right, is the new metal made of magnesium and silicon carbide nanoparticles. The right piece is made up 86 percent magnesium and 14 percent silicon carbide nanoparticles. This new metal (it’s known as a metal nanocomposite) tested off the charts for how much weight it can withstand before breaking. It also showed great stability at high temperatures.
And, the metal nanocomposite is environmentally friendly. There’s a lot of magnesium lying around. So scaling up production would not lead to environmental damage according to the researchers.
The potential uses for this type of metal are endless. Imagine cars made of this metal. The lighter weight would translate to better fuel efficiency and more money for us. Or, a lighter spacecraft. The researchers believe it could even be used in mobile electronics. Will my iPhone bend? Not with this metal nanocomposite.
We’re still a little ways off from seeing these type of metals used in everyday products. Still, the work done by these UCLA material scientists and others will pave the way for new materials in the future.