As one of the hardest materials on Earth, diamonds find themselves the benchmark for much materials science research, as engineers work to fashion tough new structures that can outperform the best nature has to offer. A team at University of California, Irvine (UCI) has now created a nanoscale carbon lattice that boasts a much greater strength-to-density ratio than diamonds.
The new design developed by the UCI research team is what’s known as a nanolattice. These porous structures consist of struts and braces made from carbon (just like diamonds themselves), which are arranged into a three-dimensional lattice pattern that offers an excellent strength-to-density ratio.
For decades, these nanolattices have been based on a design that uses trusses arranged in a cylindrical manner. The UCI researchers attribute their breakthrough to a departure from this tradition, instead using a series of plates in their place.
“Previous beam-based designs, while of great interest, had not been so efficient in terms of mechanical properties,” says corresponding author Jens Bauer, a UCI researcher in mechanical & aerospace engineering. “This new class of plate-nanolattices that we’ve created is dramatically stronger and stiffer than the best beam-nanolattices.”
While these types of plate-based nanolattice structures have been theorized to offer superior strength to other designs, manufacturing them hasn’t been so easy. The UCI team says it has now proven the theories to be on the money by taking a novel approach to successfully put one together.
That involved a complex 3D printing technique, where a laser is focused inside a droplet of ultraviolet-light-sensitive liquid resin. This turns the resin into a solid polymer, which can then be worked into the microscopic plates, which measure as thin as 160 nanometers. Tiny holes in the plates allow for excess resin to be removed from the finished product, which then undergoes pyrolysis when it is heated to 900 °C (1,652 °F) in a vacuum for one hour.
According to the team’s experiments, the resulting carbon nanolattice improved on the average strength of cylindrical beam-based architectures by up to 639 percent and increased the average rigidity by 522 percent.
“While the theoretical performance of these structures had been predicted before, we were the first group to experimentally validate that they could perform as well as predicted, while also demonstrating an architected material of unprecedented mechanical performance," says Lorenzo Valdevit, UCI professor of materials science & engineering.
One of the areas the researchers believe nanolattices like this one could make a real difference is in the field of aerospace, where engineers are continually on the hunt for low-density materials that can offer great strength.
The research was published in the journal Nature Communications.
Source: University of California, Irvine
