Scientists Discover How to Bend and Stretch Diamonds—the Hardest Natural Material

Diamond is known for being the hardest naturally occurring material. But any attempt to deform it will usually result in fractures due to its brittleness. This limits the material’s usefulness in some applications.

But now, an international team of scientists has found a way to make diamond bend and stretch like rubber, according to a new study published in the journal Science.

Researchers from MIT, Singapore's Nanyang Technological University and the City University of Hong Kong found that diamond in the form of extremely tiny, needle-like shapes, could be bent and stretched before snapping back to its original shape.

For their study, the scientists took thin films of artificial diamonds and etched tiny needles (nano-needles) out of them, which measured just a few hundred nanometers (billionths of a meter) across.

By prodding these tiny needles, they found that they could bend and stretch by as much as 9 percent without breaking, which is approaching the theoretical limit of diamond flexibility, according to the researchers. As a comparison, normal diamond in bulk form has a stretch limit that is significantly below 1 percent.

Subra Suresh, one of the authors of the study from MIT’s Department of Materials Science and Engineering, told Newsweek it was very “surprising” to see the amount of deformation that the diamond nano-needles could sustain.

“However, we know that at nano-scale materials behave very differently from the way do at micro-scale and macro-scale," he said.

MIT-Flexible-Diamond This scanning electron microscope image shows ultrafine diamond needles (cone shapes rising from bottom) being pushed on by a diamond tip (dark shape at top). These images reveal that the diamond needles can bend as much as 9% and still return to their original shape. MIT

The findings could lead to the use of diamond nano-needles in a diverse set of applications, according to the scientists. For example, they could be used to deliver drugs into cancer cells, encode data in computer systems or improve the accuracy of magnetic resonance imaging (MRI).

Diamonds and their origins continue to provide researchers in various fields with fascinating insights. For example, a recent study, also published in the journal Science, describes how diamonds have revealed that pockets of water may lie as deep as 500 miles into the Earth’s mantle.

And another paper, published in the journal Nature Communications, reported that diamonds from a meteorite that fell to Earth in 2008, originated from a lost planet of the early Solar System.