Properties of metal materials: in order to make more rational use of metal materials and give full play to their role, it is necessary to master the performance (service performance) of zero and components made of all kinds of metal materials under normal working conditions and the properties (technological properties) that materials should have in the process of hot and cold processing.
The properties of materials include physical properties (such as specific gravity, melting point, electrical conductivity, thermal conductivity, thermal expansion, magnetism, etc.), chemical properties (corrosion resistance, oxidation resistance), and mechanical properties (mechanical properties). The technological performance of the material refers to the ability of the material to adapt to cold and hot processing methods.
Eliminating the diffusion interface through the formation of single crystals is considered to be the standard strategy to reduce diffusivity, for example, the practice of manufacturing superalloy single crystal blades in the high temperature application of turbine engines. However, the team believes that even in single crystal metals, the high diffusivity cannot be suppressed at higher temperatures. At higher homologous temperature, the equilibrium vacancy concentration in the lattice increases significantly, which inevitably increases the atomic diffusivity.
In 2020, an important achievement in Science by Luke et al showed that they found a metastable structure of very fine grains, namely Schwarz crystal structure, in pure copper. The team mentioned that although it contains an extremely high density interface, the structure shows very high thermal stability at high temperatures close to the melting point to prevent grain coarsening.
Therefore, the research team believes that it is meaningful to study whether this stable Schwarz crystal structure can inhibit the diffusion of atoms in the alloy at high temperature.