Scientists investigated a metallic Alloy made of chromium, cobalt, and nickel (CrCoNi)and they found out that these three combinations have the highest toughness ever recorded on Earth. It has impressive strength and ductility, the scientists have called "outstanding damage tolerance". Not just that, the strength of the alloy improves as it gets colder.
The study published by a team of scientists from Lawrence Berkeley National Laboratory (Berkeley Lab) and Oak Ridge National Laboratory, described the findings as "record-breaking".
"When you design structural materials, you want them to be strong but also ductile and resistant to fracture," says metallurgist Easo George, Governor's Chair for Advanced Alloy Theory and Development at Oak Ridge National Laboratory and the University of Tennessee.
The study examined the fracture toughness values of the CrCoNI- a subset of a class of metals called high entropy alloys (HEAs). 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, a Newscenter report said.
"The toughness of this material near liquid helium temperatures (20 kelvin, -424 Fahrenheit) is as high as 500 megapascals square root meters. In the same units, the toughness of a piece of silicon is one, the aluminium airframe in passenger aeroplanes is about 35, and the toughness of some of the best steels is around 100. So, 500, it's a staggering number," said research co-leader Robert Ritchie, a senior faculty scientist in Berkeley Lab's Materials Sciences Division and the Chua Professor of Engineering at UC Berkeley.
The scientists also experimented with another alloy that also contains manganese and iron (CrMnFeCoNi) nearly a decade ago. According to Sciencealert, The previous experiments on CrMnFeCoNi and CrCoNi had been conducted at liquid nitrogen temperatures, up to 77 Kelvin (-196 degrees celsius, -321 degrees Fahrenheit). The team pushed it even further, to liquid helium temperatures. The results were beyond striking.
"The toughness of this material near liquid helium temperatures (20 Kelvin, [-253 degrees celsius, -424 degrees Fahrenheit] is as high as 500 megapascals square root meters," Ritchie explains.
Adding, "In the same units, the toughness of a piece of silicon is one, the aluminium airframe in passenger aeroplanes is about 35, and the toughness of some of the best steels is around 100. So, 500, it's a staggering number."
