A metal that fills cracks within itself without human intervention could be the key to building self-healing machines and infrastructure that could save trillions in repairs and maintenance. Things get even more worrying when you consider applying this to robots, but maybe we’re already there.
Metallic parts develop tiny cracks under repeated stress, known as metal fatigue. Over time, this eventually makes them more vulnerable to breakage. The solution is obvious: use alloys that take longer to crack or replace parts more often.
But Sandia National Laboratories’ Dr. Brad Boyce has a third solution: Let the metal fill the cracks before they become a problem. So far it has shown that this can be done, albeit only on a very small scale.
Self-healing materials exist, but until now they were mostly plastic or concrete. Heat can fill cracks, but applying it contradicts its self-healing ability.
The idea that such a disruption is not impossible was first expressed in 2013 by Professor Michael Demkowicz of Texas A&M University. But at that time it was purely theoretical and derived from computer simulations. It took almost 10 years to prove that this could actually happen. But this was not the case when experimenters stubbornly tried to translate Demkowicz’s ideas into reality.
Visiting scientists were using Sandia’s facilities to observe how nanoscale cracks form in platinum when its tips are pulled at a frequency of 200 Hz. During the first 40 minutes, cracks formed as expected, but then 18 nanometers of a crack filled before regrowth in another direction.
Boyce was aware of Demkowicz’s work and briefed him. Demkowicz built a computer model to compare what was done and confirmed that it was an example of what he predicted.
Obviously, as long as the behavior is limited to platinum, it cannot be relevant for large-scale applications such as collapsing bridges or aircraft engines. The scale of the problem caused by metal fatigue is so great that affecting even a small part of it can make an extraordinary difference.
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