Scientists stunned after cracked piece of metal self-healed in experiment

Like something from an X-Men movie, a piece of cracked metal has seemingly healed itself in the middle of an experiment.

While the human body can somewhat self-heal itself for cuts and even have severed limbs (occasionally) reattached, we don't fancy our chances if we were cut in half and someone tried to sew us back together.

Tell that to this piece of metal, which somehow fused itself back together and was almost as good as new.

In a 2023 study, a team from Sandia National Laboratories and Texas A&M University was conducting experiments on the resilience of metal.

The researchers used a transmission electron microscope technique that pulled the ends of a 40-nanometer-thick piece of platinum 200 times every second.

The team made an accidental discovery on damage fatigue (Jose A. Bernat Bacete / Getty)

This caused something known as fatigue damage, with repeated stress or motion causing microscopic cracks to form.

These tend to grow until the naked eye might see them, and then, the whole device can fail.

The platinum was suspended in a vacuum, and although there was damage fatigue, the team saw the seemingly impossible. After about 40 minutes of observing the sheet, the platinum started to fuse back together and effectively heal itself.

Material scientist Brad Boyce from Sandia National Laboratories was dumbfounded by the findings and said: "This was absolutely stunning to watch first-hand."

"We certainly weren't looking for it. What we have confirmed is that metals have their own intrinsic, natural ability to heal themselves, at least in the case of fatigue damage at the nanoscale."

While it's true that there are self-healing materials (namely plastics), this could be a metallic breakthrough. Boyce reiterates that cracks in metals only tend to get bigger, with basic equations suggesting such a healing process would be unlikely.

The study says that the first known incident of metal 'healing' itself without human intervention could overturn 'fundamental scientific theories in the process'. The idea that damaged bridges, airplanes, and more can reverse damage caused to them could make them last longer and altogether safer.

Can metal really heal itself? (Dan Thompson / Sandia National Laboratories)

Boyce continued: "From solder joints in our electronic devices to our vehicle’s engines to the bridges that we drive over, these structures often fail unpredictably due to cyclic loading that leads to crack initiation and eventual fracture.

"When they do fail, we have to contend with replacement costs, lost time and, in some cases, even injuries or loss of life. The economic impact of these failures is measured in hundreds of billions of dollars every year for the U.S."

In 2013, an assistant professor at the Massachusetts Institute of Technology’s Department of Materials Science and Engineering started chipping away at conventional materials theory. Now a full professor at Texas A&M, Michael Demkowicz published a new theory based on computer simulations, suggesting that metal should be able to 'heal' itself under certain conditions.

Boyce concludes by saying that it's all well and good in simulations and vacuums, but there are questions about its potential use in real-world situations: "The extent to which these findings are generalizable will likely become a subject of extensive research.

"We show this happening in nanocrystalline metals in vacuum. But we don’t know if this can also be induced in conventional metals in air."