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.

Refining grain size can effectively enhance the coercivity of bulk sintered NdFeB permanent magnets while ensuring high uniformity in magnetic properties. Key steps for grain refinement in sintered NdFeB magnets and current industrial equipment status had been described. During rapid solidification, high cooling rates effectively suppress α-Fe phase formation and reduce fragmentation difficulty. For cerium-rich magnets, trace additions of co-associated rare earth elements like La and Y help decrease the growth width of rapidly solidified flakes. Quantification of liquid volume per unit time during production proves crucial for structural consistency in rapid-solidified products. In powder preparation, regulation and adaptive control of hydrogen decrepitation process achieve preliminary powder refinement. Different jet mill configurations exhibit distinct characteristics, with fluidized bed jet mills being the most prevalent equipment, where airflow velocity at nozzle intersections in grinding chambers determines powder refinement efficiency. Regarding sintering, beyond conventional processes, spark plasma sintering emerges as an effective approach for achieving densification and suppressing abnormal grain growth. For powders with particle sizes below 2 μm, pressureless forming technology successfully resolves the forming challenges inherent to ultrafine powders.

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.

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.

Undercut is one of the key factors limiting the iterative upgrading of etched metal lead frames, and attenuating or eliminating the undercut is a common challenge faced by etch engineers, equipment manufacturers, and potion developers. Copper corrosion inhibitors as an anti-undercut additive were added to the acidic copper chloride etchant. Based on the principle of anti-undercut additive, the effective anti-undercut additive and its use of the concentration were screened out through the static and dynamic etching experiments. Finally, a kind of lead-frame product was used to verify the improvement effect of anti-undercut additive on the uniformity of etching size. It provides a feasible method for the improvement and enhancement of the etching process in the metal lead frame industry, and at the same time fills the research gap of anti-side-etching agents in the metal lead frame industry.

A novel self-supported three-dimensional electrocatalyst is proposed for the development of efficient and low-cost electrocatalysts to address the key challenges in electrolytic water hydrogen production technology. Ni₄₀Zr₄₀Ti₂₀ amorphous alloy precursor was alloyed with 3% Pt and Pd, and then combined with the dealloying technique to prepare flexible self-supported nanoporous/amorphous alloy composite catalysts with a honeycomb nanoporous structure. The alloyed Pt material required only 32 mV overpotential at 10 mA/cm² current density, and the alloyed Pd porous material required 52 mV overpotential at a current density of 10 mA/cm², Pt alloying was superior to Pd, and the porous PtNi/amorphous composite HER (hydrogen evolution reaction) performance was better than that of commercial Pt/C catalysts. The excellent electrolytic water performance of the porous PtNi/amorphous composites was attributed to their submicron honeycomb porous structure and sponge-like nanoporous structure, which exposed more catalytically active sites while ensuring the structural stability of the catalyst. Moreover, the compressive lattice strain effect was introduced due to the replacement of noble metal lattice sites by smaller nickel atoms, thus optimising the hydrogen adsorption energy. This not only opens up new avenues for developing hydrogen evolution reaction (HER) catalysts with self-supporting structures, high flexibility, and low platinum content, but also holds significant scientific importance for gaining deeper insights into alloy effects in catalytic processes.

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.

Using tungsten argon arc welding to prepare ER308L stainless steel deposited metal, and the effects of solution treatment at 1 050 ℃ for 2 hours on its microstructure and high-temperature tensile properties at 350 ℃ were studied. The results show that solid solution treatment promotes the partial dissolution of δ ferrite into γ austenite, reduces the δ/γ phase interface, simplifies the complex dislocation structure, and transforms the columnar grains of austenite into smaller equiaxed ones. The average grain size decreased from 384 to 81 μm. Solid solution treatment also reduces the ferrite content from 12.2% to 4.88%, and changes the morphology from skeleton and lath to granular, making the structure more susceptible to yield deformation. These changes significantly improve the high-temperature plasticity of the deposited metal and reduce the yield strength. After solution treatment, the high-temperature elongation of the deposited metal increased from 29% to 38%, the yield strength decreased from 322 to 128 MPa, and the hardness decreased from 210 to 138 HV₅.

Zero thermal expansion materials are widely applicable in precise instruments such as optical devices, electronic equipment, and aerospace components due to their minimal volume expansion within a fixed temperature range. The strong magneto-volume effect associated with a magnetic phase transition compensates the positive thermal expansion caused by the inharmonic lattice thermal vibration, which leads to a negative thermal expansion effect. A small amount of boron was introduced into the Ho₂Fe₁₇ alloy, which leads to zero thermal expansion in a wide temperature range. The Ho₂Fe₁₇B_0.2alloy exhibited a thermal expansion coefficient of only -0.74×10^-6 K^-1 within the temperature range of 120-350 K. Comprehensive characterizations, including scanning electron microscopy, X-ray diffraction, and vibrating sample magnetometer, were conducted to analyze the microstructure, crystal structure, and magnetic phase transition behavior of the samples. The underlying mechanism for the regulation of thermal expansion behavior has also been discussed, which provides new insights and approaches for the development of advanced zero thermal expansion materials.

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.