Researchers at the Russian National Research and Technical University first discovered the best parameters for thermomechanical treatment of titanium-nickel alloys, thereby improving the technology for producing medical shape memory alloys. The new method can improve the reliability of existing surgical equipment and develop many new products. Relevant research results were recently published in "Journal of Metals".
Shape memory alloy is a material that can recover its shape after being severely deformed. At present, the most widely used shape memory alloy based on titanium-nickel alloy is used in medical implants and intelligent medical equipment with high reliability requirements, such as removable surgical stents or vascular stents.
The maximum index of titanium-nickel alloy reversible deformation needs to be obtained by forming an ultra-fine grain structure through thermomechanical processing technology at a temperature not exceeding 600 ℃. However, the existing technology for producing titanium nickelide is carried out at a temperature of 800°C to 900°C, and therefore, it is impossible to obtain a large-scale shape memory alloy with an ultrafine grain structure. Researchers from the Russian Research and Technical University discovered for the first time the thermomechanical treatment parameters of titanium-nickel alloys, which enabled large-scale titanium-nickel shape memory alloys to obtain not only the required nanostructures, but also enhanced their functional properties.
Viktor Komarov, a researcher at the Ultrafine Grain Metal Materials Laboratory of the Russian Research and Technical University, explained that the study found that 300°C is the boundary temperature for the transformation of titanium-nickel alloy from low-temperature deformation to high-temperature deformation, and between 300°C and 600°C Within the range, the shape memory characteristics of the deformed titanium-nickel alloy dynamic polygonal structure have reached the highest level, and this heat treatment temperature interval is the best for forming an ultra-fine grain structure and improving the functional characteristics of the titanium-nickel alloy. He said that using the nanostructured titanium-nickel alloy obtained according to the new technology not only greatly reduces metal consumption, but also improves the reliability of the alloy's shape memory effect.
Victor Komarov said that in the research process, researchers obtained the deformation map of titanium-nickel alloy for the first time, and studied the formation process of shape memory alloy structure at a temperature below 600 ℃, which is very important for the nanostructure of titanium-nickel alloy. Formation is of great significance. He also said that analyzing the data obtained can also solve the dynamic temperature range of shape memory alloy recovery and recrystallization.