New metal for lighter, fuel-efficient aircraft developed

Scientists including those of Indian-origin have developed a new super-strong structural metal which could be used to make lighter, fuel-efficient airplanes, cars and spacecraft.
The new metal with extremely high specific strength and modulus, or stiffness-to-weight ratio, is composed of magnesium infused with a dense and even dispersal of ceramic silicon carbide nanoparticles.
It could be used to make lighter airplanes, spacecraft, and cars, helping to improve fuel efficiency, as well as in mobile electronics and biomedical devices, researchers said.
The researchers including Suveen Mathaudhu from University of California, Riverside and Sanjit Bhowmick, from US-based company Hysitron found a new way to disperse and stabilise nanoparticles in molten metals and 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 the principal investigator Xiaochun Li, from University of California, Los Angeles (UCLA).
Structural metals are load-bearing metals; they are used in buildings and vehicles. Magnesium, at just two-thirds the density of aluminium, 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 nanometres into magnesium added significant strength, stiffness, plasticity and durability under high temperatures.

The 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.
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. This stabilises the particles' dispersion and prevents clumping.
The study was published in the journal Nature.