On May 1, "Nature" reported the latest research results of Liu Yanhui's group on metal glass in the Institute of Physics, Chinese Academy of Sciences. Metal glass refers to a metal material with disordered structure on the atomic scale. Since its discovery in 1960, researchers have developed metallic glasses based on various elements. However, the amorphous alloy is a typical multi-component alloy material, the formation process is extremely complicated, and the composition space composed of multiple components is very large. The current "one experiment, one sample" material research method not only leads to low efficiency in the exploration of new materials, but also lacks systematicness in the experimental data obtained, making it difficult for people to fully grasp the main laws of amorphous alloy formation and the performance control mechanism.
The research team designed a metallic glass formed by the combination of three metals, iridium / nickel / tantalum and boron. The glass transition temperature of this metallic glass has reached 1162K, and the supercooled liquid region is 136K, which is higher than most current metallic glasses All are wide. Compared with the existing metallic glass, the Ir / Ni / Ta (B) metallic glass developed by the author has high strength at high temperature: 3.7 gigapascal at 1000K. Among them, their glass-forming ability is characterized by a critical casting thickness of 3 mm, indicating that small-scale parts used in high temperature or harsh environments can be easily obtained through thermoplastic molding. At the same time, the authors used this simplified combination method to screen some promising alloys using the previously reported correlation between glass-forming ability and resistivity. Because the method is non-destructive, a series of physical properties can be tested on the same sample. In short, the reported method has strong practicability and has important reference value for discovering other combinations of glass metals.
Design and combination of Ir / Ni / Ta (B) bulk metallic glass forming alloy
In recent years, Liu Yanhui's research group is committed to the independent design and development of high-throughput experimental techniques and methods suitable for amorphous alloys, and to explore new amorphous alloy materials with comprehensive properties that can meet application needs; combining experimental big data to study the formation of amorphous alloys Mechanism and performance regulation mechanism, and finally realize the on-demand design of high-performance amorphous alloy materials. The research team has made a series of progresses, such as the discovery of a new type of metallic glass material with superplasticity at room temperature (Science, 315: 1385, 2007), and established the relationship between the formation of shear bands and glass transition during the deformation of metallic glass (Physical Review Letters (103: 065504, 2009). Experiments have proved that metal glass has a non-uniform structure on the nanometer scale (Physical Review Letters, 106: 125504, 2011), and revealed the cause of the atomic structure of secondary relaxation in metal glass (Nature Communications, 5: 3238, 2014), designed and developed a high-throughput preparation and characterization technology for rapid screening of metallic glass materials (Nature Materials, 13: 494, 2014), and proposed micro-nano that is suitable for complex alloy materials and can simultaneously control the composition and structure Manufacturing Technology (Nature Communications, 6: 7043, 2015), etc. (Comprehensively compiled from Institute of Physics, Chinese Academy of Sciences, iNature, etc.)