A Cracked Piece of Metal Self-Healed In Experiment That Stunned Scientists (sciencealert.com) 16
alternative_right writes: 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 the observation is unprecedented, it's not wholly unexpected. In 2013, Texas A&M University materials scientist Michael Demkowicz worked on a study predicting that this kind of nanocrack healing could happen, driven by the tiny crystalline grains inside metals essentially shifting their boundaries in response to stress... That the automatic mending process happened at room temperature is another promising aspect of the research. 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 under 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.
While the observation is unprecedented, it's not wholly unexpected. In 2013, Texas A&M University materials scientist Michael Demkowicz worked on a study predicting that this kind of nanocrack healing could happen, driven by the tiny crystalline grains inside metals essentially shifting their boundaries in response to stress... That the automatic mending process happened at room temperature is another promising aspect of the research. 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 under 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.
I've known this for years. (Score:2)
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I wouldn't say that I've known this, but this does seem like a very small leap of logic considering that metals have long been known to be able to cold weld when in space. When to chunks of identical metal and cut apart in space, or cut apart on earth and then carefully etched to remove oxidation once in space, when put back together, they become one object again. When there is no oxidative barrier, the lattice just rejoins together. This story seems like it is the same effect. And my non-scientific guess i
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Stunned? (Score:2)
Scientists shrugged and said "neat" (Score:1)
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While probably a lot more accurate, it just doesn't convey the "eureka" moment.
Excited might be a much better word than stunned. Because it's a dead lock that there are some people who are really excited about this.
Re: Scientists shrugged and said "neat" (Score:1)
Yeah, cold welding (Score:5, Informative)
The effects of cold welding are reasonably well known in vacuum conditions; it would not be a surprise if this effect is essentially attributable to it. Would be nice to be proven otherwise though, particularly if such effects could be seen within Earth's ambient atmosphere at STP conditions.
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From the summary: "the experiment was carried out in a vacuum"
The effect isn't just attributable to it. They got excited about observing vacuum welding. There is no chance of it happening in ambient atmosphere.