In a new study, researchers discovered that “nanoarchitected” materials, or materials designed from precisely pattered nanoscale structures, could be used to develop impact-resistant products such as lightweight armor, protective coatings, and blast shields. These researchers have developed an ultralight material made from nanometer-scale carbon struts that gives it material toughness and mechanical robustness.
The research study was conducted by engineers from Massachusetts Institute of Technology (MIT) (Cambridge, Massachusetts, USA), California Institute of Technology (CalTech) (Pasadena, California, USA), and ETH Zürich (Zürich, Switzerland). Members of the research team have published their results in the latest issue of Nature Materials.
After researchers shot microparticles at the material at supersonic speed, they found that it had prevented the miniature particles from tearing through it. This test confirmed that the material—thinner than the width of a human hair—is not only efficient at absorbing impacts, but is more resilient than steel, Kevlar, aluminum, and other impact-resistant materials.
“The same amount of mass of our material would be much more efficient at stopping a projectile than the same amount of mass of Kevlar,” says Carlos Portela, assistant professor of mechanical engineering at MIT and the study’s lead author.
What’s more, this new carbon-based, nanoarchitected material could provide a lighter, tougher alternatives to Kevlar and steel.
“The knowledge from this work… could provide design principles for ultra-lightweight impact resistant materials [for use in] efficient armor materials, protective coatings, and blast-resistant shields desirable in defense and space applications,” says co-author Julia R. Greer, a professor of materials science, mechanics, and medical engineering at Caltech, whose lab led the material’s fabrication.
Due to their pattered nanometer-sale structures, nanoarchitected materials were seen as potentially lighter and tougher than comparable materials. But this potential had largely been unrealized until the Portela-Green team studied the materials under conditions of fast deformation, such as during high-velocity impacts.
At Caltech, the team fabricated a nanoarchitected material using a two-photon lithography technique and constructed a repeating lattice pattern composed of microscopic struts before they finally arrived at their finally arrived at their ultralight carbon material.
Back at MIT, they performed microparticle impact experiments to test the material’s resilience to extreme deformation. Using ultrafast lasers, the researchers were able to control the speed at which microparticle projectiles impacted the nanoarchitected material made of two different densities. They found that the denser material was more resilient and embedded microparticles within it rather than allow them to tear through.
Upon closer inspection, the team observed that while the microscopic struts and beams within the denser material had been impacted by the projectiles, the surrounding lattice architecture had remained intact.
“We show the material can absorb a lot of energy because of this shock compaction mechanism of struts at the nanoscale, versus something that’s fully dense and monolithic, not nanoarchitected,” Portela says.
“Nanoarchitected materials truly are promising as impact-mitigating materials,” he adds “There’s a lot we don’t know about them yet, and we’re starting this path to answering these questions and opening the door to their widespread applications.”
Source: MIT News, https://news.mit.edu.