A team of engineers at the Massachusetts Institute of Technology has successfully designed a new 3D material with five percent the density of steel and ten times the strength. By compressing and fusing flakes of graphene, a two-dimensional form of carbon, the sponge-link configuration is one of the strongest and lightest known materials.
The new findings, reported in the journal Science Advances, show that the crucial aspect of the new 3D form is its unusual geometrical configuration, not the material itself. The discovery suggests that similar strong, lightweight materials could be made from a variety of materials by creating similar geometric features.
Using heat and pressure, the team compressed small flakes of graphene, producing a strong, stable structure resembling the form of some corals and microscopic creatures called diatoms. The shapes, which feature an enormous surface area in proportion to their volume, proved to be remarkably strong.
To test the strength and mechanical properties of the lightweight material, the MIT researchers created a variety of 3D-printed gyroid models.
The new configurations, made in the lab using a high-resolution, multimaterial 3D printer, were mechanically tested for their tensile and compressive properties. Their mechanical response under loading was simulated using the team’s theoretical models. The results from the experiments and simulations matched accurately.
Many other possible applications of the material could eventually be feasible, the researchers said, for uses that require a combination of extreme strength and light weight.
“You could either use the real graphene material or use the geometry we discovered with other materials, like polymers or metals,” said Markus Buehler, the head of MIT’s Department of Civil and Environmental Engineering (CEE). According to Buehler, the new design gains similar advantages of strength combined with advantages in cost, processing methods, or other material properties (such as transparency or electrical conductivity).
“You can replace the material itself with anything,” Buehler said. “The geometry is the dominant factor. It’s something that has the potential to transfer to many things.”
Also: Read more Materials & Coatings tech briefs.
Transcript
00:00:00 Graphene, in its two-dimensional form, Graphene is thought to be the strongest of all known materials. But translating that two-dimensional strength into useful three-dimensional materials has posed quite the challenge to researchers for decades. But now a team of MIT engineers has successfully designed a new 3-D material with 5% the density of steel and 10 times the strength.
00:00:28 Making it one of the strongest lightweight materials known. And by analyzing the material's behavior down to the level of individual atoms, they were also able to produce a mathematical framework that can accurately predict experimental results. To test their material, the researchers printed 3-D models made purely of commercial plastic and subjected them to various compression tests, to see how much they could handle before the structure
00:00:54 begins to crumble. Here we see two 3-D gyroid models made from the same exact materials. Their only difference is one is composed of thicker walls than the other. Once stress is applied, we almost immediately noticed two very different reactions. The model composed of thinner, more flexible walls enabled it to fail gradually upon increasing deformation. While the other with thicker stiffer walls
00:01:17 is able to store much more deformation energy which has been released in a more severe explosion like manner. Ultimately, their new findings show that the crucial aspect of the new 3D forms has more to do with their unusual geometrical configuration, than with the material itself. Which suggests that similar strong lightweight materials could be made from a variety of materials with similar geometric features.
00:01:40 Having the ability to tune the mechanics of a material by simply adjusting its geometry opens the door to a wide variety of practical applications. Including strong, lightweight, structural materials for airplanes, cars, buildings, and other large-scale applications. Because of their continuous porous geometry and large surface area they could also have applications for filtration and energy storage.
