Scientists from Belgorod create alloys with high strength and ductility for low temperatures
A team of scientists from Belgorod State University (BelSU) have developed a unique alloy composed of iron, cobalt, nickel, chromium and carbon, capable of maintaining its strength at a temperature of -150°C and below.
According to the developers, the material is also cost-effective and can be widely applied in systems used in the exploration of space, the World Ocean, the Arctic and Antarctic.
At present, systems designed to operate at extremely low temperatures use so-called austenitic steels. But their strength, ductility and other mechanical properties are often insufficient in environments such as outer space, or for creating critical elements of cryogenic equipment.
“Our alloy’s properties surpass all commercial analogues at room and cryogenic temperatures alike. At the liquid nitrogen temperature of -196°C, it is 50 percent stronger than the best analogue and has an excellent ductility of 24 percent. In combination with the excellent crack toughness, this provides an ideal balance of mechanical properties,” said Dmitry Shaisultanov, senior researcher at BelSU.
He added that the use of carbon as well as higher iron content contribute to an even higher strength and lower cost. The alloy’s high mechanical properties ensure the so-called TRIP effect, the scientists explained. The combination of high strength and ductility is the result of a change in the material’s crystallographic structure that occurs in the process of cold plastic deformation.
“Such alloys are attractive because they have deep drawing characteristics, meaning they can be used to make stronger thin-walled hollow parts. Also, their use opens up a wide range of possibilities for systems that operate in extremely low temperatures, primarily in the exploration of outer space and airspace, the World Ocean, the Arctic and the Antarctic,” Dmitry Shaisultanov added.
The results obtained during the study also expand the understanding of the mechanisms that determine the behavior of alloys capable of the TRIP effect under various conditions. This will enable a more accurate choice of materials and processing techniques to create products with the necessary combinations of mechanical properties, the scientists explained.