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New ‘uncuttable’ material could create tomorrow’s bike locks and body armor

Uncuttable Proteus material

Imagine any material that you do not want to be susceptible to cutting under any circumstances. That could be security doors, bike locks, protective equipment like body armor or, heck, even shoe soles. These are just a handful of the applications that Proteus is aiming for.

Developed by researchers from the United Kingdom’s Durham University and Germany’s Fraunhofer Institute, Proteus is described, boldly, as the “first manufactured non-cuttable material.”

It’s a lightweight material with just 15% the density of steel but which, in tests, has proven uncuttable using angle grinders, drills, or ultra-high-pressure water jets. Although its outer layer can be compromised, once these cutting implements hit its embedded ceramic “nuggets” it causes the angle grinder or drill to vibrate against them in such a way that it blunts the cutting (or non-cutting) disc or drill bit.

“We developed the material for the U.K. governmental agency to increase the protection level of the national infrastructure against forcible entry,” Stefan Szyniszewski, an assistant professor of applied mechanics in Durham’s Hierarchical Materials and Structures Group, told Digital Trends. “We were inspired by [the] abalone shell and grapefruit peel, which are biological, hierarchical structures. They are cellular structures within cellular structures with 7-12 levels of hierarchy. Human-made material reaches 4-5 levels of the hierarchy.”

The material is created by mixing a metallic powder with a foaming agent and then adding ceramic nuggets. It’s then heated in a furnace, which causes the compacted powdered metal to melt and the mixture to rise like a loaf of bread. It’s then cooled slowly, and, as Szyniszewski said, “presto, we have a cellular metal with ceramic inserts.”

In an abstract describing their work, the researchers write that: “Our architecture derives its extreme hardness from the local resonance between the embedded ceramics in a flexible cellular matrix and the attacking tool, which produces high-frequency vibrations at the interface. The incomplete consolidation of the ceramic grains during the manufacturing also promoted fragmentation of the ceramic spheres into micron-size particulate matter, which provided an abrasive interface with increasing resistance at higher loading rates.”

Right now, it’s still a work in progress. But Szyniszewski is confident that it could have multiple real-world applications including the ones listed up top in this article. When it arrives in its first commercial product remains to be seen. Still, you can expect to hear the name Proteus (named after the shape-changing mythical god of Greek mythology) a whole lot more in the years to come.

A paper describing the work, titled “Non-cuttable material created through local resonance and strain rate effects,” was recently published in the journal Scientific Reports.

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