High entropy superalloy (HESA), as a research hotspot in the field of metal structural materials, has attracted wide attention due to its potential application value in extreme environments. The composition characteristics and microstructure design of high entropy superalloy are systematically described. In terms of element composition, the high entropy system is constructed by using the ratio of multiple components with equal or near equal atomic ratio. In terms of structure, the performance of face-centered cubic solid solution is optimized through the synergistic interaction between the matrix and the ordered precipitated phase. Studies have shown that HESA can maintain excellent strong plastic matching over a wide temperature range (room temperature -1 200 ℃), and its mechanical stability is due to the synergistic effect of multi-scale strengthening mechanisms, including lattice distortion strengthening caused by solid solution atoms, second phase strengthening caused by nanoscale ordered precipitates, and grain boundary strengthening achieved by grain boundary engineering. Finally, the research and application prospects of high entropy superalloys are prospected.

The strength of Q690DR steel decreases with the increase of tempering temperature, and the -40 ℃ impact toughness increases with the decrease of quenching temperature, and the increase of tempering temperature between 640-680 ℃. Controlling the heat treatment condition, it can ensure the steel meets engineering application requirements for new high-pressure hydrogen storage vessels. Through the slow strain rate tensile test with electrochemical dynamic hydrogen charging, the elongation rate of Q690DR was reduced by 3%, and the area shrinkage was reduced by 14.1%, compared with the tensile test results under air condition. It showed that Q690DR has a low susceptibility to hydrogen embrittlement under such condition. The hydrogen desorption curves of Q690DR under different heating rates, placement times, and hydrogen charging current densities were tested through thermal desorption sepctrometry TDS. The low-temperature hydrogen desorption activation energy of Q690DR was calculated to be Ea=13.39 kJ/mol, and the high-temperature hydrogen desorption activation energy of Q690DR was calculated to be Eb=117.51 kJ/mol. The hydrogen diffusion coefficient of Q690DR is 9.85×10^-7 cm²/s. After hydrogen charging, the diffusible hydrogen in the matrix can escape completely after being holding for more than 12 hours. The hydrogen content charged in the Q690DR matrix increases with the increase of hydrogen charging current density. In addition, with the help of atomic force microscope AFM, we observed the enrichment behavior of hydrogen in the grain boundaries and the second phase after hydrogen charging. Based on the changes in potential difference, we can judge that the grain boundaries are shallow hydrogen traps and the second phase is deep hydrogen traps.

The grain boundary diffusion process of hot-deformed magnet with additional pressure was studied. The properties and microstructure of the magnet after diffusion were analyzed. The coercivity of the magnet increases from 14.19 to 24.36 kOe when diffusion with no pressure. But the height of the c-axis of the magnet increases significantly. A large number of non-magnetic phases enter the interior of the magnet and the orientation decreases significantly, which resulting in a drastic deterioration of the remanence. The remanence decreased from 14.71 to 10.00 kGs. The volume expansion in the c-axis direction of the magnet was control-led when the pressure was applied to the diffusion process. The area fraction of the rare-earth rich phase was reduced and the orientation was increased. The drastic deterioration of remanence is inhibited. After grain boundary diffusion, the coercivity mechanism of the magnet was changed and the pinning effect of the diffusion magnet was significantly enhanced, which may be the main reason for the increase of coercivity. Finally, the properties of the magnet obtained by grain boundary diffusion with additional pressure were B_r=13.71 kGs, Hcj=18.63 kOe, (BH)_max=46.44 MGOe.

With the rapid progress of China′s power electronics and new energy industries, the demand for efficient, multi-purpose and environmentally friendly soft magnetic alloys is also gradually increasing. Existing research situation on the performance regulation of silicon steel is discussed. Based on the characteristics of the soft magnetic material, we points out the core performance index of iron loss, and points out the necessity of improving the resistivity of the material through composition regulation and other means, so as to achieve the maximum energy efficiency. Secondly, the influence of alloy composition, inclusion, defect, grain size, residual stress and crystal structure on the performance of silicon steel is discussed. In addition, we points out that with the progress of material science and nanotechnology, the research on the relationship between microstructure and performance of silicon steel will be more in-depth, and people will be able to more precisely regulate silicon steel in order to achieve better magnetic performance.

Review of casting magnesium alloys containing Nd is performed. In terms of the microstructure, mechanical properties and corrosion resistance, the effect of Nd on the grain size and second phase precipitation of magnesium alloys is analyzed, the influence of Nd on the ultimate tensile strength, yield strength and elongation of magnesium alloys is discussed, and the effect of Nd on the corrosion resistance of magnesium alloys is reviewed, with the aim of providing references for the design and development of casting magnesium alloys containing Nd.

High purity dysprosium and terbium metals serve as the fundamental raw materials in various fields, including permanent magnet materials, magnetostrictive materials, magneto-optical storage materials, magnetic refrigeration materials and electric light source materials. The calcium thermal reduction method and the intermediate alloying method used in the preparation of industrial pure dysprosium and terbium metals are summarized, and the vacuum distillation method, zone melting method and solid state electromigration method are described in detail. The technology of hydrogen ionization arc melting, electrochemical deoxidation and solid phase external inspiratory are also summarized. Finally, we considers the future development direction of high purity dysprosium and terbium metals from the perspective of market orientation and operability, and provides reference for the development of high purity rare earth metals dysprosium and terbium industries.