Early in the morning of August 28th Professor Zhang Xiancheng and Academician Tu Shandong's team from the School of Mechanical and Power Engineering, East China University of Science and Technology, published an article titled Dual-scale chemical ordering for cryogenic properties in CoNiV-based in Nature The latest research results of alloys.
With China's continuous exploration in extreme environments such as the polar regions, deep sea, deep space and energy, the low-temperature and harsh working conditions have posed unprecedented challenges to the comprehensive mechanical properties of metal structural materials. In such environments, structural materials not only need to have high strength, but also must take into account excellent ductility and fracture toughness. However, the coordinated improvement of low-temperature strength and toughness has always been a worldwide challenge in engineering applications. On the one hand, many traditional alloys undergo a ductile-brittle transformation when the temperature drops, losing their ductility and toughness, which can easily lead to sudden failure of structural components. On the other hand, common strengthening mechanisms (such as precipitation strengthening) enhance strength by hindering dislocation movement. However, if the second-phase particles are too large or distributed at grain boundaries, stress concentration will occur within the material, which may instead become a potential hazard for crack initiation. For this reason, the organizational control methods suitable for low-temperature working conditions are still very limited and difficult to meet the demands of major low-temperature projects for highly reliable key components.
A collaborative research by Professor Zhang Xiancheng and Academician Tu Shandong's team from East China University of Science and Technology, in collaboration with Professor Dierk Raabe's team from the Max Planck Institute in Germany, has discovered that through the synchronous and precise regulation of material entropy and enthalpy, dual-scale nanostructures of high-density short-range ordered structures (SRO) and nano-long-range ordered structures (NLRO) can be formed within Coniv-based entropy alloys. This structure enables the material to achieve ultra-high tensile strength and low-temperature fracture toughness at temperatures close to liquid nitrogen. This research achievement will provide a brand-new material design concept for the manufacturing of key components serving in extremely low-temperature environments.
The Key Laboratory of Pressure System and Safety of the Ministry of Education at East China University of Science and Technology is the first author's institution and the first corresponding institution of the paper. Dr. Lu Tiwen and Professor Sun Binhan are the co-first authors of the paper. Professor Zhang Xiancheng and Professor Dierk Raabe from the Max Planck Institute for Sustainable Materials in Germany are the co-corresponding authors of the paper. Dr. Li Yue and Dr. Dong Xizhen's team (Max Planck Institute for Sustainable Materials), Professor Dai Sheng's team (East China University of Science and Technology), Professor He Lunhua's team (China Spallation Neutron Source), and Professor Li Zhiming's team (Central South University) participated in the research work. In recent years, the team led by Professor Zhang Xiancheng and Academician Tu Shandong from East China University of Science and Technology, with the support of the National Key Research and Development Program and other projects, has conducted systematic research on the material design and anti-fatigue manufacturing of important equipment in extremely low-temperature environments, in response to the urgent needs of implementing major cryogenic projects.