A metal that repairs itself? It’s not science fiction

In the film “Terminator 2: Judgment Day” In 1991, a time-traveling, shape-shifting android named T-1000 was made of a Liquid metal and had a unique quality. When he was hit by explosions or bullets, he would repair himself.

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

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

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

Material fatigue occurs when metal, including parts of machines, vehicles and structures, suffer microscopic gouges after being exposed to repeated movement, damage that tends to worsen over time.

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

In experiments at the Sandia National Laboratories government facility in New Mexico, the researchers used a technique that pulled the ends of tiny pieces of metal about 200 times per second. Initially, a crack formed and spread.

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

“It is a metallurgical process that is known to occur when two relatively smooth and clean metal surfaces are brought together to reform atomic bonds”said Brad Boyce, a materials scientist at Sandia National Laboratories, who helped lead the study published in the journal Nature.

‘Unlike the self-repairing robots in the movie’Terminator‘, this process is not visible on a human scale. It happens at the nanoscale and we have yet to be able to control it.” added.

The metal pieces were about 40 nanometers thick and a few micrometers wide. While the repair was seen in the experiments only on platinum and copper, Boyce said the simulations indicated it can occur on other metals and that it is “totally plausible” that alloys such as steel can exhibit this quality.

“It is possible to imagine materials adapted to take advantage of this behaviour”said.

“Given this new knowledge, there may be alternative materials design strategies or engineering approaches that could be designed to help mitigate fatigue failure. Furthermore, this new understanding may shed light on fatigue damage in existing structures, improving our ability to interpret and predict it.”he explained.

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

Demkowicz thought, correctly, that under certain conditions subjecting the metal to stress that should normally worsen fatigue-related cracks might have the opposite effect.

“My guess now is that tangible applications of our findings will take another 10 years to develop.”held.

“When I first made my predictions, some members of the press said that I was working on a T-1000. That’s still science fiction.” Demkowicz said.

“But at the end of (TV series) ‘Battlestar Galactica,’ the crew adapted the technology Cylon (a fictional robot race) to help repair fatigue damage to their ship, making the metal behave more like organic tissue that can heal itself from its injuries.”

“I would say that what we are working on is more similar to the example of ‘Battlestar Galactica’”he expressed.

The self-repair was observed in a very specific environment using a device called an electron microscope.

“One of the big questions that remain open from the study is whether the process also occurs in air, not just in the vacuum environment of the microscope. But even so, it still has important ramifications for studies on fatigue in space vehicles or that associated with underground cracks that are not exposed to the atmosphere.”Boyce said.

Source: Reuters