Self-Healing Minerals: A Breakthrough in Engineering
Scientists have noticed that the mineral heals itself, which has never been observed before. And if this process can be fully understood and controlled, we can be at the beginning of a whole new era of engineering.
A Remarkable Discovery
A team from Sandia National Laboratories and Texas A&M University tested the elasticity of the metal using special transmission electron microscopy technology to pull the tips of the metal 200 times per second. They then observed the self-healing, on a very small scale, of a 40-nanometer-thick piece of platinum suspended in a vacuum.
Understanding Fatigue Damage
Cracks resulting from the type of stress described are known as fatigue damage: repetitive stress and movement that cause microscopic tears, eventually leading to failure of equipment or structures. Surprisingly, after about 40 minutes of observation, the crack in the platinum began to heal and heal again before moving in the other direction again.
“It was absolutely amazing to see it firsthand,” says materials scientist Brad Boyes of Sandia National Laboratories. “We certainly weren’t looking for it. We confirmed that metals have their own natural ability to self-heal, at least when damaged at the nanoscale.”
Potential Applications
These are exact terms, and we don’t yet know exactly how this happens or how we can use it. However, when you factor in the cost and effort required to repair everything from bridges to engines to telephones, it’s impossible to tell just how much of a difference self-healing minerals can make.
While the sighting is unprecedented, it is not entirely unexpected. In 2013, Texas A&M University materials scientist Michael Dimkovich worked on a study that predicted the possibility of this type of nanocrack healing, caused by microcrystalline grains within minerals that drastically change their boundaries in response to stress.
Dimkovic has also been working on this latest study, using updated computer models to show that his decade-old theories about metal self-healing at the nanoscale are consistent with what is happening here. The occurrence of spontaneous reduction at room temperature is another promising aspect of research. It usually takes a lot of heat for a metal to change its shape, but the experiment was done in a vacuum. It remains to be seen whether the same process will occur in ordinary metals in a typical environment.
The Role of Cold Welding
A possible explanation involves a process known as cold welding, which occurs at ambient temperatures when metal surfaces come close enough that their atoms stick together. Typically, thin layers of air or contaminants interfere with the process; In environments such as the vacuum of space, pure metals can be close enough to literally stick together.
“I hope this result encourages materials researchers to think that, under the right conditions, materials can do things we never expected,” says Dimkovic.
The study is published in the journal Nature.
Source: Science Alert
