Tirtha Paul, our science faculty, delves into the groundbreaking discovery of self-healing metals, a phenomenon observed for the first time, offering the potential for a revolution in engineering.
File this under ‘That’s not supposed to happen!’: Scientists observed a metal healing itself- something never seen before. If this process can be fully understood and controlled, we could be at the start of a whole new era of engineering.
In a study published in July, a team from Sandia National Laboratories and Texas A&M University was testing the resilience of the metal, using a specialized transmission electron microscope technique to pull the ends of the metal 200 times every second.
They then observed the self-healing at ultra-small scales in a 40-nanometer-thick piece of platinum suspended in a vacuum.
They then observed the self-healing at ultra-small scales in a 40-nanometer-thick piece of platinum suspended in a vacuum.
Cracks caused by the kind of strain described above are known as fatigue damage: repeated stress and motion that causes microscopic breaks, eventually causing machines or structures to break.
“This was absolutely stunning to watch first-hand,” said materials scientist Brad Boyce from Sandia National Laboratories when the results were announced. “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.”
These are exact conditions, and we don’t know yet exactly how this is happening or how we can use it. However, if you think about the costs and effort required for repairing everything from bridges to engines to phones, there’s no telling how much difference self-healing metals could make.
Another promising aspect of the research is that the automatic mending process happened at room temperature. Metal usually requires lots of heat to shift its form, but the experiment was carried out in a vacuum; it remains to be seen whether the same process will happen in conventional metals in a typical environment. A possible explanation involves a process known as cold welding, which occurs at ambient temperatures whenever metal surfaces come close enough together for their respective atoms to tangle together.
Typically, thin layers of air or contaminants interfere with the process; in environments like the vacuum of space, pure metals can be forced close enough together to literally stick.
This finding will encourage material researchers to consider that under the right circumstances, materials can do things we never expect.
The research was published in Nature.
