UCLA researchers have developed a super strong and light weight metal that shows exceptional strength and modulus. The stiffness to weight ratio of the metal is impressive and it can find application in many industries including aviation, automobiles and space technology.
The newly developed metal can be use in mobile electronics and biomedical devices as well. It could improve fuel efficiency if it can be produced on a commercial scale. The research paper detailing the project has been published in the journal Nature. Structural metals have excellent load bearing capacity and can be used in manufacturing, buildings and vehicles.
The research was conducted at UCLA Henry Samueli School of Engineering and Applied Science.
Magnesium, at just two-thirds the density of aluminum, is the lightest structural metal. Silicon carbide is an ultra-hard ceramic commonly used in industrial cutting blades. The researchers' technique of infusing a large number of silicon carbide particles smaller than 100 nanometers into magnesium added significant strength, stiffness, plasticity and durability under high temperatures.
Lead researcher Xiaochun Li, Raytheon Chair in Manufacturing Engineering at UCLA said, "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."
Researchers say the metal may be just the first of many groundbreaking manufacturing materials. That's because they've invented a new technique for infusing metals without nanoparticles without hurting the metal's structural integrity.
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.
Previous research showed ceramic nanoparticles have a tendency to clump together when added to metals, making them stronger but weakening their plasticity. Researchers solved this problem by dispersing the nanoparticles in a molten magnesium zinc alloy.
The researchers’ new silicon carbide-infused magnesium demonstrated record levels of specific strength — how much weight a material can withstand before breaking — and specific modulus — the material’s stiffness-to-weight ratio. It also showed 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.
However, 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.
The paper’s other authors from UCLA include 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.
The other authors on the paper are Hongseok Choi, of Clemson University; Xiaolong Ma, of North Carolina State University; Sanjit Bhowmick of Hysitron, Inc. of Minneapolis; and Suveen Mathaudhu of UC Riverside.
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.