UCLA researchers have developed a new metal by combining magnesium and ceramic silicon carbide nanoparticles which has record-breaking strength to weight ratio. The lightweight metal has extremely high specific strength and modulus. It can be used as light structural metal. Structural metals are used as load-bearing metals in structures and vehicles. The research team used magnesium as it is the lightest structural metal.
Using ceramic silicon carbide nanomaterials, the research team at UCLA Henry Samueli School of Engineering and Applied Science was able to improve the strength of magnesium. The light metal can find application in automobiles, mobile electronics, biomedical devices, airplanes and in construction as well.
The high-performance light-weight metal is composed of magnesium infused with a dense and even dispersal of ceramic silicon carbide nanoparticles. The research paper detailing the project has been published in the journal Nature.
The silicon carbide-infused magnesium metal developed by the team has record breaking specific strength - the weight it can withstand before it fails. Using nanoscale ceramic particles, the research team was able to enhance strength while maintaining or even improving metals’ plasticity. Earlier projects have tested similar move with microscale particles and it wasn’t successful. The research was funded by the National Institute of Standards and Technology.
The research project was led by Xiaochun Li, Raytheon Chair in Manufacturing Engineering at UCLA. Li said, “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.”
After processing, researchers tested the magnesium, newly infused with a dense, even spread of nanoparticles. The new material showed improved strength, stiffness, plasticity and durability under high temperatures.
Because magnesium is relatively abundant and the production technology can be easily scaled up, scientists hope the metal's industrial applications will be quickly realized. And scientists don't think it will be long before they've found a new metal-nanoparticle combination with impressive potential.
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.
To further enhance the new metal’s strength, the researchers used a technique called high-pressure torsion to compress it.
“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,” Li said.
The new metal (more accurately called a metal nanocomposite) is about 14 percent silicon carbide nanoparticles and 86 percent magnesium. The researchers noted that magnesium is an abundant resource and that scaling up its use would not cause environmental damage.
The paper’s lead author is Lian-Yi Chen, who conducted the research as a postdoctoral scholar in Li’s Scifacturing Laboratory at UCLA. Chen is now an assistant professor of mechanical and aerospace engineering at Missouri University of Science and Technology.
The study was co-authored by Jia-Quan Xu, a graduate student in materials science and engineering; Marta Pozuelo, an assistant development engineer; and Jenn-Ming Yang, professor of materials science and engineering.