Indestructible Terminator-style killer robots move one step closer to reality as scientists discover self-healing metals
- Scientists have witnessed metal healing without any human intervention
- Self-healing planes, engines and even robots could now be plausible ideas
The idea of indestructible killer robots may sound like something straight out of the Terminator movie.
But they could soon become a reality, as scientists have just witnessed metal healing itself for the first time, without any human intervention.
A US-based study has overturned everything we thought we knew about metals by revealing that cracks from wear and tear can actually mend themselves under certain conditions.
It's a discovery that has the potential to revolutionise engineering, with the prospect of self-healing engines, planes and even robots now on the horizon.
'This was absolutely stunning to watch first-hand,' said Brad Boyce, a scientist at Sandia National Laboratories who led the study with Texas A&M University.
'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.'
Metals that are currently used to build vital infrastructure such as bridges and planes undergo a lot of repeated stress and motion which causes microscopic cracks to form over time.
While this fatigue damage usually causes machines to break, Mr Boyce and his team witnessed the nano-sized fracture shrink by 18nm.
This was an entirely unexpected discovery as scientists only intended to evaluate how cracks would spread through a 40-nm-thick piece of platinum when pressure was applied.
They were 40 minutes into the experiment when the damage reversed, as a 't-junction' crack fused back together as if it were never there in the first place.
Then, as more pressure was applied, the crack regrew in a different direction, as amazed scientists watched through a microscope.
'From solder joints in our electronic devices to our vehicle's engines to the bridges that we drive over, these structures often fail unpredictably due to cyclic loading that leads to crack initiation and eventual fracture,' Mr Boyce continued.
'When they do fail, we have to contend with replacement costs, lost time and, in some cases, even injuries or loss of life. The economic impact of these failures is measured in hundreds of billions of dollars every year for the U.S.
'Cracks in metals were only ever expected to get bigger, not smaller. Even some of the basic equations we use to describe crack growth preclude the possibility of such healing processes.'
While much remains unknown about self-healing, scientists believe that a process known as cold welding may have played a role.
This can occur at the tip of metal fatigue, allowing bare metals to 'join' when compressed under contact.
Their study comes 10 years after Michael Demkowicz, of Massachusetts Institute of Technology, put forward a similar theory about self-healing metals.
He promoted the idea that nanocracks rely on the generation of crystal defects known as 'disclinations' to heal within metals.
In this study, researchers also acknowledged that different crystalline materials with different grain shapes and textures could be impacted by this in different ways.
Their nano-sized platinum was primarily tested in conditions with no oxygen so they believe there is an opportunity explore non-vacuum conditions even further.
Mr Boyce continued: 'The extent to which these findings are generalisable will likely become a subject of extensive research.
'We show this happening in nanocrystalline metals in vacuum. But we don't know if this can also be induced in conventional metals in air.'
Ten years on from his own study, Mr Demkowicz praised this latest research and expressed his future hopes.
He said: 'My hope is that this finding will encourage materials researchers to consider that, under the right circumstances, materials can do things we never expected.'
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2023-07-20 09:58:06Z
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