A new study reveals the profound properties of a simple metal alloy:
Scientists have measured the highest toughness ever recorded, of any material, while investigating a metallic alloy made of chromium, cobalt, and nickel (CrCoNi). Not only is the metal extremely ductile – which, in materials science, means highly malleable – and impressively strong (meaning it resists permanent deformation), its strength and ductility improve as it gets colder. This runs counter to most other materials in existence.
The team, led by researchers from Lawrence Berkeley National Laboratory (Berkeley Lab) and Oak Ridge National Laboratory, published a study describing their record-breaking findings in Science on Dec. 2, 2022. "When you design structural materials, you want them to be strong but also ductile and resistant to fracture," said project co-lead Easo George, the Governor's Chair for Advanced Alloy Theory and Development at ORNL and the University of Tennessee. "Typically, it's a compromise between these properties. But this material is both, and instead of becoming brittle at low temperatures, it gets tougher."
CrCoNi is a subset of a class of metals called high entropy alloys (HEAs). All the alloys in use today contain a high proportion of one element with lower amounts of additional elements added, but HEAs are made of an equal mix of each constituent element. These balanced atomic recipes appear to bestow some of these materials with an extraordinarily high combination of strength and ductility when stressed, which together make up what is termed "toughness." HEAs have been a hot area of research since they were first developed about 20 years ago, but the technology required to push the materials to their limits in extreme tests was not available until recently.
[...] Now that the inner workings of the CrCoNi alloy are better understood, it and other HEAs are one step closer to adoption for special applications. Though these materials are expensive to create, George foresees uses in situations where environmental extremes could destroy standard metallic alloys, such as in in the frigid temperatures of deep space. He and his team at Oak Ridge are also investigating how alloys made of more abundant and less expensive elements – there is a global shortage of cobalt and nickel due to their demand in the battery industry – could be coaxed into having similar properties.
Though the progress is exciting, Ritchie warns that real-world use could still be a ways off, for good reason. "When you are flying on an airplane, would you like to know that what saves you from falling 40,000 feet is an airframe alloy that was only developed a few months ago? Or would you want the materials to be mature and well understood? That's why structural materials can take many years, even decades, to get into real use."
Journal Reference:
Dong Liu, Qin Yu, Saurabh Kabra, et al., Exceptional fracture toughness of CrCoNi-based medium- and high-entropy alloys at 20 kelvin, Science, 378, 2022. DOI: https://doi.org/10.1126/science.abp8070
(Score: 3, Insightful) by MIRV888 on Thursday February 02, @01:37AM (3 children)
Turbine manufacturers are going to have a conniption fit.
(Score: 2) by mhajicek on Thursday February 02, @02:54AM
Yup, can't wait until someone asks me to machine super tight tolerance parts from that overnight.
The spacelike surfaces of time foliations can have a cusp at the surface of discontinuity. - P. Hajicek
(Score: 0) by Anonymous Coward on Thursday February 02, @03:51AM
Is this really what you anticipate?
https://www.vocabulary.com/dictionary/conniption [vocabulary.com]
(Score: 2) by driverless on Saturday February 04, @10:21AM
Chunk Norris OTOH refers to it as "shiny putty".
(Score: 2) by darkpixel on Thursday February 02, @01:54AM (1 child)
Did you get management's input on that?
You forgot that you also want it to be lightweight, cheap and quick to manufacture, patented, and able to be sold at extortionately high prices.
(Score: 2) by mcgrew on Thursday February 02, @04:47PM
And don't forget, easy for planned obsolescence. I worked with a guy once who said he was a quality control inspector for GE, and was fired for letting too many long-lasting bulbs through.
Carbon, The only element in the known universe to ever gain sentience
(Score: 4, Informative) by Anonymous Coward on Thursday February 02, @04:01AM (2 children)
TFA sure has a bunch of nonsense in the first paragraph.
Um, no, ductile and malleable do not mean the same thing at all in materials science.
Maybe they meant to say the material is both ductile and malleable? But then they go on to say literally the complete opposite:
But this material was just claimed to be "extremely ductile" (or did they mean malleable?), which means it is easily deformed under tension (or did they mean compression?), and such deformation is "permanent" (in the sense that the material does not return to its original shape when the force is removed).
It makes no sense that a material which is easily deformed can simultaneously be "impressively" resistant to such deformation...
(Score: 3, Informative) by Anonymous Coward on Thursday February 02, @04:43AM
This was wrong I suppose. A highly ductile material could still, in principle, require a very large stress before it begins the "plastic deformation" stage that is characteristic of such materials.
But still, the actual paper's abstract seems pretty clear that this is not what they mean by "strong". They are talking about fractures and ductility so that sounds like tensile strength (how much stress it can take before it breaks). It also seems clear that what is interesting about this material is not that it is both strong and ductile, but that it has these properties at extreme cryogenic temperatures.
(Score: 2) by mcgrew on Thursday February 02, @04:49PM
The trouble with science reporting is that the reporter doesn't understand the subject he is reporting on, and the scientists assume he knows stuff that he doesn't.
Carbon, The only element in the known universe to ever gain sentience
(Score: 2) by its_gonna_be_yuge! on Thursday February 02, @04:52PM (1 child)
A mixture of Cr, Co, Ni is heavy and expensive. Not too many real-world applications. Getting Cobalt is
always an ethical challenge.
(Score: 0) by Anonymous Coward on Thursday February 02, @07:35PM
Yeah, but Say Hello to the Toughest Material on Earth. Hello.