2023-07-23 17:10:02
News JVTech A cracked piece of metal “heals” itself and shocks scientists. The beginning of a new era for engineering?
Published on 07/23/2023 at 19:10
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What if metal could heal itself? It seems absolutely impossible, yet scientists themselves are amazed to have achieved this feat. But is it really reproducible on a large scale?
A real discovery
Scientists from
Sandia National Laboratories and Texas A&M University
have made an extraordinary discovery that could be a game-changer in modern engineering: they have observed a metal in the process of scarring, a phenomenon never seen before. This promising discovery opens up exciting prospects for the development of more resistant and self-healing materials.
The groundbreaking experiment was conducted by testing the resilience of the metal using a specialized transmission electron microscope, pulling on its ends at a mind-boggling 200 times per second. The study material was a tiny piece of platinum only 40 nanometers thick, suspended in a vacuum.
Cracks resulting from these intense stresses, commonly referred to as “fatigue damage”, are known to lead to catastrophic failures of machinery and structures after repeated stresses and movements. However, after about 40 minutes of careful observation, the researchers witnessed an astounding phenomenon: the crack in the platinum began to repair and coalesce before heading in a different direction.
This fascinating observation highlights an intrinsic and natural ability of metals to heal themselves, at least at the nanoscale. If this process can be fully understood and controlled, it could usher in an unprecedented era of engineering.
The finding is not entirely unexpected, as in 2013, Texas A&M University materials scientist Michael Demkowicz predicted that this type of nanocrack healing was possible due to tiny crystal grains present inside metals. These grains are able to shift their boundaries in response to stress.
A particularly promising aspect of this finding is that the self-repair process took place at room temperature. Normally, metals require intense heat to change shape, but this experiment was performed in a vacuum environment. The researchers now hope to test whether this same process can occur under more common conditions involving conventional metals.
One of the possible mechanisms explaining this scarring is “cold welding”. It occurs at room temperatures when metal surfaces are close enough together for their atoms to intertwine. In interference-free environments, like the vacuum of space, pure metals can get close enough to literally merge. It can be seen a bit like two metals that come into intense friction, heat up and weld together.
The potential applications of this discovery are immense, touching various fields such as the construction of structures, the manufacture of machines and even telephones. If self-healing metals could be brought under control, it could revolutionize the way we design and repair materials in the future, making costly maintenance operations obsolete.
By challenging traditional theories about the fatigue life of materials, this breakthrough encourages materials researchers to explore new opportunities and envision that materials could do unexpected things. The idea of self-healing materials could also inspire new approaches to designing strong and durable materials.thereby reducing the costs and environmental impact associated with their manufacture and maintenance.
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