It’s not science fiction: they’re testing a mineral that repairs itself

In the 1991 movie “Terminator 2: Doomsday,” a time-travelling android named the T-1000 is made of liquid metal and has a unique quality: when hit by an explosion or bullets, it repairs itself.

Self-healing metal is still just science fiction, right? Apparently not.

Scientists today revealed how pieces of pure platinum and copper spontaneously restore fatigue cracks in the material during nanoscale experiments designed to study how fatigue cracks form and propagate in a metal under stress.

Experts have expressed optimism that the feature could be engineered into minerals to make self-healing machines and structures in the relatively near future.

Material stress occurs when metal, including parts of machinery, vehicles, and structures, suffers microscopic pitting after being subjected to repeated motion, a damage that tends to worsen over time.

Physical fatigue can cause catastrophic failure in areas including aviation — jet engines, for example — and infrastructure, such as bridges and other structures.

In experiments conducted at the Sandia National Government Laboratories facility in New Mexico, the researchers used a technique that pulled the tips of the tiny metal pieces about 200 times per second. At first, a crack formed and spread out.

But about 40 minutes into the experiment, the metal fused together again. The researchers called this repair “cold welding”.

said Brad Boyce, a materials scientist at Sandia National Laboratories, who helped lead the study published in the journal Nature.

He added, “Unlike the self-repairing robots in the Terminator movie, this process is not visible on a human scale. It happens on a nanoscale and we still have to control it.”

The metal pieces were about 40 nanometers thick and a few micrometers wide. While the reformation was only observed in experiments with platinum and copper, Boyce said simulations indicated that it could occur in other metals and that it was “quite plausible” for alloys such as steel to exhibit this quality.

“It is possible to imagine materials adapted to take advantage of this behavior,” he said.

“Given this new knowledge, there may be alternative materials design strategies or engineering approaches that can be designed to help mitigate fatigue failure. Furthermore, this new understanding may shed light on stress damage to existing structures, improving our ability to interpret and predict them. , ” It is to explain.

In the past, scientists have created some self-healing materials, mostly plastics. Study co-author Michael Dimkovic, professor of materials science and engineering at Texas A&M University, predicted self-healing in metals a decade ago.

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Dimkovic believed, correctly, that under certain conditions, exposing the metal to stresses that would normally exacerbate fatigue-related cracks might have the opposite effect.

“My guess now is that concrete applications of our findings will take another 10 years to develop,” he said.

“When I first presented my forecast, some members of the press said I was working on a T-1000. It’s still science fiction,” Dimkovic said.

“But at the end of Battlestar Galactica (TV series), the crew adapts Cylon technology (a fictional robot race) to help repair fatigue damage to their ship, making the metal act like organic tissue so that it can heal itself from its wounds.” “I would say what we’re working on is very similar to the Battlestar Galactica example,” he said.

Self-repair has been observed in a very specific environment using a device called an electron microscope.

“One of the big questions that remains open from the study is whether the process also occurs in air, rather than just in the microscopic vacuum environment. But even so, it still has important implications for studies of spacecraft stress or those associated with underground cracks,” Boyce said. Don’t get exposed to the atmosphere.” (Reuters NA)