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A team led by researchers at UCLA has created a super-strong yet light structural metal nanocomposite with extremely high specific strength and modulus. Composed of magnesium infused with a dense and even dispersal of ceramic silicon carbide nanoparticles, the new material could be used to make lighter airplanes, spacecraft, and cars, helping to improve fuel efficiency, as well as in mobile electronics and biomedical devices.
The science behind it
The researchers devised a new way of dispersing and stabilizing nanoparticles in molten metals. They also developed a scalable manufacturing method that could pave the way for more high-performance lightweight metals.
“It’s been proposed that nanoparticles could really enhance the strength of metals without damaging their plasticity, especially light metals like magnesium, but no groups have been able to disperse ceramic nanoparticles in molten metals until now,” said Xiaochun Li, the principal investigator on the research and Raytheon Chair in Manufacturing Engineering at UCLA, in the group's press release. “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.”
Sidestepping loss of plasticity
The researchers’ new silicon carbide-infused magnesium demonstrated record levels of specific strength and specific modulus, as well as superior stability at high temperatures. Ceramic particles have long been considered as a potential way to make metals stronger. However, with microscale ceramic particles, the infusion process results in a loss of plasticity.
Nanoscale particles, by contrast, can enhance strength while maintaining or even improving metals’ plasticity. But nanoscale ceramic particles tend to clump together rather than dispersing evenly, due to the tendency of small particles to attract one other. To counteract this issue, researchers dispersed the particles into a molten magnesium zinc alloy. The newly discovered nanoparticle dispersion relies on the kinetic energy in the particles’ movement. This stabilizes the particles’ dispersion and prevents clumping.
The researchers’ work was recently published in Nature.