Sintered metal porous materials are a special type of metal material that integrates structure and function. They are widely used in industries such as coal chemical, petrochemical, aerospace, new energy, semiconductor, smelting, and environmental protection, and play an important role in the development of the national economy This paper introduces the types of sintered metal porous materials and elaborates on their applications in filtration and separation, fluid distribution control, catalytic loading, and enhanced mass and heat transfer. It predicts the development trend of sintered metal porous materials, which will continue to develop towards material composite, pore size refinement, structural gradient, widespread application, and multifunctionality in the future.

W-Cu composites is a structural and functional integrated material composed of W and Cu, exhibiting exceptional properties such as high hardness, strength, thermal stability, wear resistance, low coefficient of thermal expansion, good ablative resistance and conductivity. It finds extensive applications in electronic, electrical, aerospace and military industries. However, commercial W-Cu composites prepared through high temperature infiltration or liquid phase sintering often possess coarse structures with inferior mechanical properties. As China's industrial modernization progresses rapidly, higher requirements are also put forward for the comprehensive properties of W-Cu composites. As a result, the preparation technology of W-Cu powder and blocks has greatly accelerated the development of W-Cu composites in recent years. This review summarizes the mechanisms and characteristics of different forming technologies and powder preparation techniques for W-Cu composites, along with an analysis of their microstructure and properties. Finally, future trends for the development of W-Cu composites are discussed.

The mechanical properties of wire and arc manufactured (WAAM) magnesium (Mg) alloys can be improved by solution treatment, whilst its impact on the wear performance remains unclear. The impact of solution treatment duration (0, 2, 4, 6, 8, 10 and 12 h) under 400 ℃ on the microstructure and sliding wear behaviors was investigated and characterized using optical microscopy (OM), scanning electron microscopy (SEM), multifunctional friction testing machine, electron backscatter diffraction (EBSD) and nanoindentation. The results show that the size of grain increases from 9.9 μm to 105.6 μm, as well as the content of precipitation and hardness of the microstructure reduces from 4.8% to 0.7% and from 73.4HV to 60.3HV respectively, as the solution treatment duration increases from 0 h (as WAAMed) to 12 h. However, the wear loss volume reduces and then increases with increasing the solution treatment duration. The minimum wear loss, 19.2% compared to the untreated one, is achieved by 6 h solution treatment. Such a tendency can be affected by the hardness gradient of the tribology transformation subsurface microstructure. The tribology-induced hardening effect of WAAM AZ91 increases with the solution treatment duration, attains at around 40% by 6 h solution treatment. The hardness of the tribology transformation layer initially increases and then decreases with the solution treatment duration, and the peak hardness of 1.66 GPa is achieved by 6 h solution treatment.

Additive manufacturing of 316L stainless steel has broad application prospects in the field of nuclear energy due to its excellent processing accuracy, surface quality, comprehensive mechanical properties, and corrosion resistance. However, when nuclear structural materials are used in irradiation environments, the defects generated by irradiation can lead to a decrease in material performance. In order to ensure the stability of the performance of AM 316L stainless steel under irradiation environment, the study of its irradiation damage effect has gradually become a hot topic of attention both domestically and internationally. Therefore, the research progress on the structure, properties, and radiation resistance of AM 316L stainless steel commonly used in the field of nuclear energy is reviewed, and some suggestions for future research directions are proposed in the article.

The coercivity of sintered Nd-Fe-B magnets can be improved and the cost can be reduced when light rare earth is used as the diffusion source to replace part of heavy rare earth. In this paper, the heavy rare earth Tb in Tb-Al-Ga alloy was partially replaced by low-cost light rare earth Pr. The effects of Pr substitution on the magnetic properties and microstructure of sintered dual-main-phase Nd-Ce-Fe-B magnets and sintered singlemain-phase Nd-Fe-B magnets were studied, and the coercivity strengthening mechanism was revealed. With Pr60Tb20Al10Ga10 as the diffusion source, the coercivity of the grain boundary diffusion magnet increases obviously. Compared with the single main phase magnet, the diffusion depth of the double main phase magnet is significantly increased. Pr with low melting point preferentially enters the magnet and improves the wettability of grain boundary phase. This causes more Tb elements to enter more deeply in magnet, forming a shell structure with high magneto-crystalline anisotropy field surrounding main phase grain, and then improving the coercivity of GBDed magnet.

Rare-earth permanent magnet radiation-oriented integral magnetic rings are a crucial type of permanent magnet material, widely utilized in high-end electromechanical products, precision measuring instruments, and advanced defense technologies, among other fields. The advancement of radial integral permanent magnet ring preparation technology is of significant importance for promoting the leapfrog development of China's advanced equipment. This article introduces the classification and characteristics of rare earth integral permanent magnetic rings from three aspects: magnetic ring materials, preparation processes, and orientation methods. It focuses on the current research progress of the radial forming process and mechanical properties of sintered rare earth radial integral permanent magnetic rings. These advancements provide new ideas for the development of high-performance sintered rare earth radial ring technology.

Powder metallurgy technology is a scientific technology manufacturing metal powders, alloy powders, non-metallic powders, compound powders, or materials or products made from these powders through forming and sintering. As the metal powder in the preparation process is easy to adsorb oxygen and oxidation, in the sintering process is not easy to fully deoxidise, and with the development and use of alloying elements, chemically active alloying elements are easy to combine with oxygen elements, increasing the difficulty of deoxidisation, so that powder metallurgy materials are prone to oxygen content exceeding the standard, which seriously affects the performance of powder metallurgy materials. This paper discusses the influence of oxygen content on the preparation process and mechanical properties of various metals and alloys, and introduces the methods of controlling the oxygen content of some metals in the powder metallurgy process. It focuses on the research progress of oxygen content control of iron-based powder metallurgical materials, titanium and titanium alloy powder metallurgical materials, copper alloys, refractory metal tungsten and molybdenum powder metallurgical materials, and summarises the current status of the research and looks forward to the development trend of its future.

In high-voltage power transmission systems, W-Cu electrical contact alloys are subjected to complex environments involving high-temperature arc ablation, SF6 gas erosion, and mechanical wear, necessitating a combination of high conductivity, strength-toughness, and corrosion resistance. This paper systematically reviews the microstructure regulation mechanisms of preparation technologies such as electroless plating, melt infiltration, spark plasma sintering (SPS), mechanical alloying, and microwave sintering, and discusses the influence of different processes on the interfacial bonding characteristics of W/Cu. The study comprehensively analyzes The effects of metal particles, ceramic phases, and fiber reinforcements in enhancing arc erosion resistance through mechanisms such as grain refinement strengthening and second-phase strengthening, while summarizing the synergistic regulation mechanisms of reinforcement phase morphology distribution and interfacial reactions on the material's overall performance. Current research demonstrates that multicomponent composite reinforcement systems effectively mitigate the conductivity-mechanical property trade-off. For instance, microwave-sintered materials with nano dual-phase reinforcement maintain high electrical conductivity even under significant hardness improvement. Future efforts should focus on developing core-shell structured nano-reinforcements, external field-assisted sintering technologies, machine learning design platforms, and full-lifecycle performance evaluation systems to address the challenge of conductivity-strength synergy. With the integration of multidisciplinary approaches, W-Cu alloys are expected to deliver next-generation high-performance contact material solutions for smart grids and extreme-environment electrical devices.

Laser powder bed fusion (LPBF) exhibits significant advantages in the manufacturing of high-entropy alloys (HEAs) with complex shapes and good strength-toughness properties. To further enhance the mechanical strength of HEAs, adding Nb element is an effective way which could enhance the solid solution strengthening and second phase strengthening effects. However, the structure features of second phase formed during LPBF is prone to brittle fracture, resulting in the significant decrease in the toughness properties of HEAs. Therefore, it is of great significance to study the effect of heat treatment post-processing on the microstructure and properties of HEAs fabricated by LPBF. The CoCrFeMnNiNb_0.15 HEAs were successfully prepared by LPBF first, and then the evolution of phase structure, mechanical properties and fracture morphology were studied after heat treatment. The results show that the heat treatment prompts the structure transformation of Nb-rich Laves phase from the continuous network to the fine and dispersively-distributed particles, and partial Nb element precipitates from the matrix structure of the FCC phase. Besides, the matrix grains also grow up along the (111) crystal orientation. With the increase of heat treatment temperature, the Laves phase and the matrix structure become coarsened gradually. Due to the weakened solid solution strengthening, grain boundary strengthening and second phase strengthening effects after heat treatment, the plastic deformation capability of the FCC phase is improved, thus resulting in the failure mode changed from brittle fracture to ductile fracture. When the heat treatment temperature is 980 ℃, the CoCrFeMnNiNb_0.15 HEAs can obtain the well-matched strength-toughness properties, which shows the product of strength and elongation of 13.2 GPa%, ultimate tensile strength of (892 ± 13.4) MPa, and elongation rate of 17.4%.

Because of its high hardness, high strength, good plasticity and excellent heat shock resistance and creep resistance, rhenium metal has been widely used in aerospace nuclear industry, catalysis field, electronics field, biomedicine and other high-tech fields. In this paper, the preparation methods of rhenium powder and rhenium products are reviewed, among which the hydrogen reduction method is the most popular. The preparation of rhenium powder is developing in the direction of increasing the purity of rhenium powder. The mature preparation methods of rhenium products include powder metallurgy, electron beam melting and chemical vapor deposition. The production cost of powder metallurgy is low, but the production of complex components is difficult. The purity of the product prepared by electron beam melting is high, but the cost is high and the production of complex components is difficult. Chemical vapor deposition method has high purity and can prepare complex components. It is often used for the preparation of thin film materials, but the cost is high. The three methods are relatively mature, and all have certain industrial production capacity. On this basis, the mechanical properties and creep properties of rhenium prepared by different methods are compared. It is concluded that rhenium prepared by hot isostatic pressing and chemical vapor deposition has better properties. However, hot isostatic pressing method has not been industrialized because of its high cost. Domestic research institutions also need to further explore advanced preparation technology, in-depth study of rhenium deformation mechanism, and explore new application fields.

TWIP steel controls stacking-fault energy to create twinned crystal organizations, enhancing ductility and strength. Although extensive research has been conducted on TWIP steels fabricated by melting, limited attention has been given to TWIP steels prepared through powder metallurgy. Furthermore, the current powder metallurgy TWIP steel samples have not fully realized their vast application potential. The materials were prepared at different temperatures and times using a combination of gas-atomized Fe-21Mn-0.7C alloy powder and fast hot pressing technology. The effects of sintering temperature and sintering time on the tissue evolution and mechanical properties of the materials and subsequent hot rolling and heat treatment to further optimize the comprehensive mechanical properties were investigated. The results show that the temperature increases, the holding time increases, the small particle size range powders are fully fused together to form a denser structure, and the grain boundary oxides have basically been depinned. At 930 °C, 40 MPa, and 12 minutes, the alloy achieves a density of 98.86%, tensile strength of 955 MPa, and extensibility of 32.8%. After hot rolling, the tensile strength can reach 1 690 MPa. After annealing, a high-strength and high-toughness steel with excellent comprehensive mechanical properties is obtained, with the tensile strength and elongation being 998 MPa and 46.2% respectively. The annealed material exhibited excellent comprehensive mechanical properties.

Copper and its alloys are renowned for their excellent thermal and electrical conductivity, and various other beneficial properties. Integrating these materials with the design flexibility offered by 3D printing technology can significantly improve the efficiency of heat exchange and current transmission. A comprehensive overview of recent advancements in 3D-printed copper and copper alloys was presented. It also provides a detailed comparison of the advantages and disadvantages of different forming methods, along with an analysis of existing challenges. Numerous studies indicate that achieving controlled shape and performance in 3D-printed components necessitates the integrated control and optimization of materials, structures, processes, and overall performance. However, the application of 3D printing technology to produce copper and its alloys still faces several hurdles. The low absorption and high reflectivity of copper towards laser energy complicate achieving desired structures through the selective laser melting and laser melting deposition processes. Additionally, the surface quality of components produced via the electron beam selective melting method is often suboptimal for precision manufacturing. Moreover, the binder jetting technology necessitates post-forming heat treatment, which can result in shrinkage and deformation issues. The potential applications for 3D-printed copper and copper alloys were explored, highlighting their contributions to the ongoing evolution and innovation within the advanced manufacturing sector.

Hot isostatic pressing (HIP) technology can be used in powder metallurgy to manufacture high-performance components, and in recent years, it has been widely applied in the fields of casting densification, diffusion bonding, and near-net-shape forming. As a green and efficient component preparation technology with simple processes and controllable properties, hot isostatic pressing powder metallurgy (HIP-PM) will be widely used in numerous industrial fields in the future, such as aerospace, nuclear power engineering, electronic information, rail transit, etc. The research progress of HIP-PM technology for duplex stainless steel (DSS) from aspects such as DSS powder preparation, the microstructure and mechanical properties of products are introduced, and corrosion resistance and the application fields and development trends of this technology are summarized.

Aluminum alloy is one of the most important nonferrous metal in the application of industry while the surface performance like hardness and wear-resistance are usually poor, restricting the further application of aluminum alloy. Laser cladding on the surface of aluminum alloy can form a metallurgical bonding coatings with substrate, which can effectively improve the surface properties of aluminum alloy. Laser cladding can also repair aluminum alloy parts, showing high application value. The laser cladding on the surface of aluminum alloy has become a hot topic at home and abroad and the related research works are increasing day by day with the continuous development of science and technology. However, there is few literature to summarize the development status of laser cladding. This paper introduces the basic knowledge of aluminum alloy laser cladding, and focuses on the current material system of laser cladding on the surface of aluminum alloy, including aluminum alloy, nickel base alloy, ceramics, high entropy alloy, etc., and briefly introduces the newly research methods and processes in this field. Finally, the development prospect of aluminum alloy laser cladding is prospected. This paper can provide reference for the researchers of laser cladding technology on the surface of aluminum alloy.

Magnesium matrix composites are widely used in various industries and have been studied in depth because of their excellent comprehensive properties, such as low density, high specific strength and high specific modulus. This paper mainly reviews the reinforcement mechanism and research progress of SiC on magnesium matrix composites, and finds that SiC can effectively balance the contradictory relationship between strength and plasticity in traditional magnesium matrix composites, and play a good reinforcing effect on magnesium matrix composites. Through the review and analysis, SiC on magnesium matrix composites reinforcement mainly has Orawan strengthening, fine grain strengthening, thermal mismatch strengthening and load transfer strengthening. Meanwhile, the size and distribution of reinforcing particles play a decisive role in strengthening magnesium alloys and determine the strengthening mechanism. For most magnesium alloys, an optimal effect is achieved when the addition of particulate reinforcement is 1 wt%. SiC particles at micro- and nano-scales are more effective in enhancing the mechanical properties of magnesium matrix composites. To achieve high-performance SiC-reinforced magnesium matrix composites, the current optimal methods include melt infiltration, powder metallurgy, stir casting, and high-energy ultrasonic processing. The application of nano-SiC reinforcements in magnesium matrix composites represents a cutting-edge research topic. Through meticulous design and fabrication, it is expected to enhance the mechanical properties, wear resistance, and corrosion resistance of magnesium matrix composites, thus holding broad application prospects in fields such as aerospace, automotive, and electronics.

In order to predict the shrinkage and deformation during the sintering process of metal green parts fabricated by binder jetting additive manufacturing (BJAM), a high-temperature creep model based on viscoelastic calculation was established to simulate the thermally induced creep behavior during the sintering process. This model establishes a connection between the microscopic and macroscopic descriptions of sintering, taking into account the effects of grain boundary diffusion, the action of gravity, grain growth, and thermal expansion on the sintering shrinkage and deformation. The parameters in the model depend on the particle size, relative density, and temperature. The numerical simulation was implemented by writing a user-defined subroutine CREEP in Abaqus, and the 316L powder widely used in industry was selected for experimental verification. The results show that the average linear shrinkage rates in the x and y directions are 11.61%, while the average linear shrinkage rate in the z direction is 12.64%. Compared with the experimental values (the average linear shrinkage rate in the x direction is 10.12%, the average linear shrinkage rate in the y direction is 10.15%, and the average linear shrinkage rate in the z direction is 11.21%), the error range is approximately 1% to 2%. This indicates that the model has a good predictive effect, especially for 316L stainless steel parts in which grain boundary diffusion is the main sintering mechanism. Optimizing and obtaining more accurate material property parameters, especially under high-temperature conditions, will help to further improve the prediction accuracy of the model.

Silicon carbide particle reinforced aluminum-silicon matrix composites have broad application prospects as structural functional materials in vehicle traffic, aerospace and precision instruments because of their high specific strength, high specific stiffness, good wear resistance and easy deformation. However, the coupling effect of thermal/stress field will occur in the preparation and processing of the composites, resulting in interface reaction, segregation of reinforcement phase, multi-scale precipitation of Si phase and intermetallic compound phase and microstructure evolution, which are unfavorable to the regulation of the mechanical properties of the composites. In this paper, the advantages and disadvantages of several mature preparation processes such as powder metallurgy, stir casting, impregnation and jet deposition are reviewed, and the effects of several preparation processes on the microstructure and properties of composites are analyzed

Binder jet 3D printing (BJ3DP) is a non-melting, high-efficiency, and cost-effective metal additive manufacturing technology. In recent years, it has shown great potential in producing complex structures, large-sized parts, and high-precision components. Compared with laser melting techniques, BJ3DP offers several advantages, such as broad material compatibility, low processing temperature, and the absence of residual stress. These features make it particularly suitable for heat-sensitive or easily oxidized metals. This paper reviews the key factors affecting the quality of metal parts produced by BJ3DP, including powder characteristics, printing parameters, and debinding/sintering processes. It focuses on the phase evolution, microstructure, and mechanical properties of various alloy systems, such as iron-based, nickel-based, magnesium-based, aluminum-based, and high-entropy alloys, etc. Finally, current challenges and future development trends were briefly outlined.

The effects of 1% TiB₂ particles as reinforcing phase on the microstructure and properties of Al-Zn-Mg-Cu alloy were studied. Al-6Zn-3Mg-Cu aluminum alloy and TiB₂/Al-6Zn-3Mg-Cu composite material were prepared using Spark Plasma Sintering (SPS) technology. The desired samples were obtained after hot forging, hot extrusion, and T6 heat treatment, followed by the study and analysis of the samples' microstructure and mechanical properties. The results indicate that there is no macroscopic segregation of alloy elements, and TiB₂ particles are uniformly distributed in the aluminum alloy matrix. The grain size of the aluminum-based composite material modified with TiB₂ is refined, the defects and pore aggregation in the structure are reduced, and the TiB₂ promotes the uniform distribution of MgZn₂ precipitation phase in the matrix. Due to the combined effects of grain refinement, improvement of microstructure, age-hardening precipitation of MgZn₂, and reinforcement from TiB₂ particles, the TiB₂/Al-6Zn-3Mg-Cu composite material achieves ultimate tensile strength, yield strength, and elongation of 539 MPa, 495 MPa, and 10.3%, respectively, showing improvements over the Al-6Zn-3Mg-Cu alloy in all three aspects.

Ti/ZrO2-Al2O3 gradient material was prepared by laser directed energy deposition technology. The microstructure, element distribution and changes of microhardness were systematically analyzed by means of scanning electron microscopy, energy spectrometer and Vickers hardness tester, and the influence of Al2O3 con‐ tent in ZrO2 ceramic powder on the microstructure and properties of the material was explored. The results show that with the increase of Al2O3 content, the mixing of the two phases is more uniform, while the cracking phenom‐ enon is more serious at the interface. The hardness of ceramic region in the sample also increases as the Al2O3 content increases. When the Al2O3 content is 30%, the hardness reaches 1344.5HV0.2, but in the binding region, the hardness increases significantly, reaching 1187.3HV0.2, only when the Al2O3 content increases to 30%.

Laser cladding was carried out to prepare Ni₃Al/Cr₇C₃ alloy coatings on 42CrMo steel. The effects of different Cr₇C₃ contents on the microstructure and wear resistance of the cladding materials were investigated using scanning electron microscopy, X-ray diffraction and wear tribometer. The results indicate that the microstructure of the Ni₃Al based cladding materials contains mainly Ni₃Al and in situ-formed Cr₇C₃. The microhardness of the laser cladding materials prepared by Ni₃Al/Cr₇C₃ alloy powder is above 550HV, and the maximum reaches 834HV. With the increase of Cr₇C₃ content, the wear resistance of Ni₃Al based cladding materials first increases and then decreases. When the Cr₇C₃ content is 25%, the wear rate of Ni₃Al based cladding materials is 0.74×10^-5 mm³/(N·m), only 14.7% of the wear rate of Ni₃Al laser cladding coating without Cr₇C₃, and the wear rate of Ni₃Al-based alloy cladding materials is only 1.669×10^-5 mm³/(N·m).

Metal based diamond composite materials have been widely used in the electronic industry and mechanical manufacturing industry due to their superior physical and mechanical properties. However, the improvement of composite material performance is limited by traditional manufacturing techniques. Additive manufacturing provides ideas for the preparation of complex structured metal based diamond composite materials. Additive manufacturing (3D printing) is a near net forming technology that transforms digital models into physical entities, with the advantage of designing and manufacturing personalized customized materials with complex structures and small anomalies. The application of 3D printing technology in manufacturing metal based diamond composite materials with better and more stable performance, while controlling production costs and reducing energy consumption, has become an inevitable trend in China's industrial development. This article summarizes the research progress of additive manufacturing technology currently used in metal based diamond composites, and puts forward prospects for further research directions in this application technology.

Nb-16Si-10Mo and Nb-16Si-10Mo-10Ti alloys were prepared by Spark Plasma Sintering (SPS) technique. The effect of sintering temperature on the microstructure and properties of the two alloys was analyzed . The results show that Nb-16Si-10Mo alloy is composed of three phases: Nbss, Nb3Si and Nb5Si3, while Nb-16Si10Mo-10Ti alloy is composed of three phases: Nbss, Nb5Si3 and Tiss, and the densities of both alloys are above 99.4%. With the increase of sintering temperature, the Vickers hardness and compressive strength of the two alloys first increase and then decrease, while the bending strength and fracture toughness gradually decrease. With the addition of Ti element, the fracture morphology appears dimple characteristics, and the fracture mode changes from brittle fracture to composite fracture, and the Vickers hardness and compressive strength of the alloy are reduced at various sintering temperatures, while the bending strength and fracture toughness are increased.

Using metallographic microscope, scanning electron microscope, oxygen-nitrogen analyzer, laser particle size analyzer, and X-ray diffraction analyzer, the characteristics of M50NiL powder prepared by plasma rotating electrode process （PREP), including the microstructure and phase composite, nitrogen-oxygen content, particle size distribution, and flowability were characterized. The results indicate that the powder has a relatively narrow particle size range, primarily distributed between 30-53 μm, with a unimodal distribution and a Gaussian distribution curve. The average particle size is 45.21 μm. The chemical composition of the powder is uniform, with high purity and no other impurities. Metal powder has low nitrogen-oxygen content with the below 0.024% of the oxygen and the below 0.025% of the nitrogen. The M50NiL powder with different particle sizes are primarily composed of α phase. The solidification structure varies with the change of the particle size: 15-53 μm consists of fine cellular and dendritic structures, whereas 53-150 μm is dendritic, and >150 μm is characterized by coarse equiaxed crystal structures. M50NiL powder has excellent physical properties and meets the technical requirements of powder bed fusion additive manufacturing.

Cu/Al laminated composites are more and more widely used because of their high cost-effective synergistic effect. However, the interface structure, microstructure of copper layer and aluminum layer of Cu/Al composites prepared by different process methods are different, and the mechanical properties are different. The difference in interface bonding characteristics leads to macroscopic quality problems such as dislocation, delamination, and copper layer surface tearing during deep processing, which seriously restricts its application in high-end fields. In this paper, the research status of atomic scale of copper-aluminum laminated composites is introduced. The research progress of molecular dynamics simulation on the interface layer structure, diffusion and solidification, the correlation between heterogeneous interface characteristics and mechanical properties of copper-aluminum laminated composites is reviewed. The advantages and disadvantages of different potential functions in molecular dynamics simulation of copper-aluminum laminated composites are analyzed. It is proposed that accurate model, reasonable force field and accurate parameters are the three basic criteria for material atomic scale simulation, which provides a reference for the study of atomic scale of metal laminated composites.

In order to investigate the influence of alloy composition on the properties of soft magnetic alloy powders, 6 groups of alloy powders with varying contents of Si, Cr, and Mn were prepared by the water-gas atomization method. The saturation magnetization and coercivity of these alloy powders were characterized employing a vibrating sample magnetometer (VSM). Subsequently, the powder was compacted into magnetic powder cores, and their magnetic properties, insulation resistance, and corrosion resistance were evaluated using an LCR tester, a soft magnetic AC tester, and a salt spray tester. The results indicate that increasing the content of Si and Cr leads to a reduction in saturation magnetization and permeability. However, it significantly enhances coercivity, magnetic loss, insulation resistance, and corrosion resistance. Conversely, the incorporation of Mn into the alloy adversely affects saturation magnetization, permeability, coercivity, and hysteresis loss while improving eddy current loss and insulation resistance.

Selective laser melting (SLM) technology has attracted much attention from the aeronautics and astronautics realm due to its advantage of high degree of freedom, high accuracy, and good mechanical properties after printing. Considering the durability and designing concept of damage tolerance of structural materials, the crack propagation rate of components applied into aeronautics is regarded as one of the key points to ensure the service safety of equipment. The research of ameliorating the crack resistance of titanium alloys through posttreatment is believed to provide valuable data guidance to the further application of SLM-printed titanium-based components in the aeronautics. In the current paper, the hot isostatic pressing (HIP) process is conducted to SLM-printed TA15 alloys as the post-treatment. Specifically, the influence of the HIP temperature on the microstructure, hardness, and crack propagation rate are investigated in details. The microstructure of the as-printed TA15 alloy HIP treated at the temperature range of 900-980 ℃ is generally identified as multi-hierarchical needle or lath-like α phase. Besides, the size of the α phase gradually coarsens along with the rise of the HIP temperature. The average length of primary α phase ranges from 60 μm to 66 μm. Whereas, the width of primary αphase significantly increases from 2.35 μm to 5.62 μm. The hardness of the HIPed specimen resultantly reduces from 35.8 to 31.9 (HRC). When the HIP temperature surpasses the phase transformation point of α to β phase, the formation of Widmannstatten structure is observed in the specimen with hardness of 32.2 (HRC). The crack propagation rate of the specimens HIP treated utilizing different parameters converges and is seldomly affected by the microstructure when the stress intensity factor range (ΔK) is within 20~50 MPa·m1/2. While the crack propagation rate gradually decreases with the rise of HIP temperature when ΔK＜20 MPa·m1/2. Coarsening of multi-hierarchical needle(lath)-like α phase enhances the deflection of crack propagation path caused by microstructure, which correspondingly retards the further propagation of cracks. Widmannstatten structure formed in the specimen HIP treated at 1 020 ℃ possesses the lowest crack propagation rate among different microstructures. In addition, the packets of α phase with various crystallographic orientation inside the β phase favors the conversion of fatigue cracks propagation path, which effectively lengthens the propagation path and reduces the crack propagation rate. In summary, the coarsened multi-hierarchical lath-like α phase in the specimen HIP treated at 980 ℃ and the Widmannstatten structure formed after HIP treatment at 1 020 ℃ benefit to the reduction of crack propagation rate. While the hardness of specimens suffers a certain loss.

The 4J29 alloy formed by MIM underwent post-treatment through Hot Isostatic Pressing（HIP）at various temperatures. The study is aimed to explore how HIP temperature influences the microstructure, coefficient thermal expansion and tensile behavior of the 4J29 alloy. The results reveal a gradual increase in alloy density with rising HIP temperature. However, beyond 1 200 ℃, the density enhancement rate decelerates, hardness decreases, and grain size exhibits accelerated growth. The leak rate follows a trend of initial decrease, reaching its minimum at 1 200 ℃, and then increasing. Before 1 200 ℃, the leak rate decreases with temperature, and beyond 1 200 ℃, it gradually rises. The optimum HIP temperature is 1 200 ℃, resulting in the alloy reaching a density of 98.54%, a leak rate of 1.2×10^-9 Pa·(m³/s), hardness of 81.3HRB, an average thermal expansion rate of 2.0×10^-6 m·℃ between 30~200 ℃ and along with a noticeable enhancement in tensile strength and elongation.

Satellite powder is a common defect powder in metal powder preparation by atomization process. Excessive satellite powder defects affect the stability of powder laying and the density of the product. This paper starts from the principle of satellite powder defect formation by atomization process, and uses ANSYS Fluent to conduct numerical simulation in three-dimensional flow field. The influence of two novel atomization tower optimization structures formed by setting a mist protection cover and a supplementary gas device on the macroscopic airflow field in the tower were studied and the control effect of the flow field optimization structure on suppressing the formation of satellite powder was analyzed. The results show that the position and height factors of the mist protection cover affect the isolation effect of powder recirculation directly, and the position factor significant influences the distribution range of the recirculation area at the same time. Placing the mist protection cover structure of 300 mm height at a distance of 200 mm from the center axis and 250 mm from the top of the atomization tower can effectively isolate the direct impact of recirculating particles on the molten droplets in the atomization region. The pressure parameter of the supplementary gas device directly affects the isolation effect of recirculating particles and the intensity of recirculating gas clusters. Placing the supplementary gas device with a pressure parameter of 0.5 MPa at a distance of 200 mm from the center axis can provide good protection for the atomization region. Both of the two novel atomization tower optimization structures can effectively suppress the collision between particles and molten droplets in the atomization region ,thus achieving the effect of inhibiting the formation of satellite powder.

In response to the application requirements of tungsten-impregnated copper material in high-tempera‐ ture gas erosion, the tungsten- infiltrated copper material (W-7Cu) experienced high-temperature gas erosion was analyzed. The focus was on the morphological features of the similar nut-shaped that appeared on the surface of W-7Cu after burning.The microstructure was observed by SEM and metallographic analysis. The loss of copper was estimated through energy spectrum. The phase structure changes was analyzed by XRD. The results show that Cu loss occurres in everywhere of the materials, and C is presented on both the outer and inner surfaces. Both of the inner and outer surfaces contain a large amount of W6C2.54 and WC phases. Under high temperature and high-speed particle flow, the C particles enters the W skeleton formed after Cu precipitating and reacts with W to form new low-melting phases, which induces the ablation accelerating.

Lithium is the lightest metal element. If 1% lithium is fused into aluminum alloy, the alloy density can be decreased by 3% and the elastic modulus can be increased by 6%. Due to its excellent strength, corrosion resistance, fatigue resistance and ductility, aluminum-lithium alloy has become an ideal lightweight high-strength material in the aerospace field. The traditional melting casting method has certain limitations when fabricating aluminum lithium alloy, such as the need for special melting casting equipment, easy to produce porosity, cracks and other defects. The need for forging, extrusion and other processes after casting increases the manufacturing cost and prolongs the manufacturing cycle. However, additive manufacturing technology can avoid these problems and provide a new solution for the processing and manufacturing of aluminum lithium alloy. In this paper, the microstructure and properties of additive manufacturing aluminum-lithium alloy are summarized, the main technology research situation of additive manufacturing aluminum-lithium alloy is concluded, and the development trend and prospect of additive manufacturing technology in the preparation of aluminum-lithium alloy in the future are analyzed.

Sintered bodies were prepared using the hot pressing sintering process from Fe-Co-Cu pre-alloyed powders of varying particle sizes. The densification, Rockwell hardness, three-point bending strength, microstructure of the two sintered bodies of different particle sizes, and interface morphology between sintered body and diamond were comparatively analyzed. Furthermore, cutting experiments were conducted to assess the cutting speed, tool life, and diamond exposure of drill bits prepared using pre-alloyed powders with varying particle sizes to further investigate their performance disparities. The results indicate that the sintered body of DB-02, prepared with pre-alloyed powder of finer particle size, exhibits higher density (96.9%)and improved toughness (with a bending strength of 1 355.7 MPa).The modified tool design also results in enhanced retention force on the diamond, leading to improved cutting efficiency, extended tool lifes, and a maximum diamond exposure height of 154.2 μm during cutting experiments.

Compared with laser and e-beam based additive manufacturing technologies, the combined 3D printing and sintering process is cheaper, but the exploration of the process parameters in the sintering stage is not comprehensive and in-depth enough. Therefore, the experiment uses screw-based 3D printing technology to prepare 17-4PH stainless steel samples, to explore the influence law of sintering process parameters (sintering temperature, heating rate and holding time) on the properties of 17-4PH stainless steel, including porosity and tensile property measurements, and to investigate the influence law of the sintering process parameters on the pore structure, microstructure and fracture morphology. The changes in the mechanical properties of the sintered samples were elaborated through the changes in the pore structure, microstructure and fracture morphology. The results show that the mechanical properties of the sintered samples are best when the sintered samples are heated up to 1 360 ℃ for 1 h at a rate of 4 ℃/min, with a yield strength of 518 MPa and a tensile strength of 693 MPa.

A TiC high manganese steel-bonded carbide with 0.1% boron addition was fabricated by powder metallurgy techiniques using TiC as hard phase and Fe, Ni, Mo, Mn, graphite C raw powders as the binder, and effects of sintering temperature on the microstructure and properties of the alloys were carried out. Microstructure observation shows that the structure of the alloy consists of black core-gray rim ceramic particles and white metallic binder, while, the ceramic particles grow gradually and its distribution become evenly with the temperature increase. The relative density of the alloy increases firstly and then decreases with the temperature increase, subsequently, the relative density of the alloy increases monotonously with the temperature increase and reaches the maximum value 98.29%. Mechanical properties results show that the hardness, transverse rupture strength (TRS) (in the as-sintered state and heat treatment state) and impact energy (IE) of the alloy increased monotonously with the temperature increase, also, reach the maximum value 63.8HRC, 1 993 MPa/1 425 MPa and 9.3 J/cm². The alloy densifies singnificantly when sintered from 1 320 ℃to 1 340 ℃, then, the hardness, TRS and IE of the alloy increases obviously. Subsequently, the increase rate of the hardness, TRS and IE of the alloy slow down which indicates the distinct role of B element in promoting densification. Boron element begins to volatilize and is exhausted completely at 1 420 ℃.The experimental alloy with B addition and the high manganese steel matrix are cast into a whole part, no obvious defects as cracks, impurities and pores are observed between the interfaces showing excellent interface bonding state and prospective long service life.

The forming process of the shape and structure of a certain electrical adjustment seat component was analyzed, and Moldflow software simulation results was used to guide the improvement and optimization of the gate type and position in the design scheme of the metal injection molding mold. Finally, the design of the metal injection molding mold is completed. Through actual production verification, the mold structure is reasonable, and the product quality of injection molding using this mold meets customer′s requirements.

The surface of sintered Ti80 alloy was strengthened by surface ultrasonic rolling (USRP) technology, and the microstructure and properties of Ti80 alloy before and after rolling were analyzed by optical microscope (OM) and scanning electron microscope (SEM). The results show that the surface strengthening effect of the sample is the best when the rolling amplitude is 10 μm. The densification effect of the sample after rolling is remarkable. The surface hardness is increased by 18.5% and the surface roughness is reduced by 86%. The tensile strength and yield strength of rolled Ti80 alloy are 992 MPa and 815 MPa, respectively, which are 15.2% and 1.3% higher than those of sintered samples, and the elongation is increased from 1.7% to 2.6%. After soaking in 4 mol/L hydrochloric acid solution for eight days, the weight loss rates of sintered and rolled titanium alloys were 20.6 mg/cm² and 10.6 mg/cm², respectively, and the weight loss rate was reduced by 48.5%, which effectively improved the corrosion resistance of Ti80 alloy.

W-Cu composites are widely used in electronic components, particularly in high-power devices. However, as packaging requirements become more demanding, the stability of these devices must be further improved. Due to the significant intrinsic differences between W and Cu, it is challenging for W-20Cu composites to simultaneously exhibit the excellent properties of both materials. Thus, structural and organizational optimization is urgently required. Tungsten particles of varying sizes （20, 10, 5, and 2 μm） for dual particle size ratio experiments were employed to control the porosity of the W framework and promote densification of the W-20Cu composite. The results show that under the sintering conditions of 1 300 °C for 2 h, the composite produced with a particle size ratio of 10:1 and a mass ratio of 7:3 achieves the highest density of 99.12%. Moreover, the material exhibites a gas permeability of 3.1×10^-11 Pa·m³/s and a maximum flexural strength of 744 MPa. Its thermal properties include a thermal conductivity of 211 W/(m·K), slightly lower than the theoretical thermal conductivity of 220 W/(m·K), and a thermal expansion coefficient of 8.91×10^-6/K. These properties meet the performance standards required for packaging materials in electronic applications.

Using AlN-CrFe as a hybrid friction modifier, copper-based powder metallurgy friction materials were sintered through a powder metallurgy method, and the influence of different preparation processes such as cold pressing pressure and sintering temperature on the performance of copper-based powder metallurgy friction materials was studied. The results show that with the increase in cold pressing pressure, the hardness and density of the friction material increase. As the sintering temperature increases, the density and hardness of the friction material gradually decrease. When the cold pressing pressure is 600 MPa and the sintering temperature is 950 °C, the friction material exhibites a higher hardness of 28.68HB and a greater density of 5.05 g/cm³. The overall friction coefficient is higher and stable during high-speed braking, and the wear rate is relatively low. The predominant wear mechanism is oxidative wear, making the friction material's comprehensive performance optimal.

ZrO₂ particle-reinforced copper-based friction materials were prepared by powder metallurgy (PM), and the effects of ZrO₂ contents on microstructure and properties of the materials were studied. The microstructure, density, porosity, hardness and friction and wear properties of the materials were characterized. The results show that the phase composition and distribution state of the copper base friction material are not changed significantly before and after the addition of ZrO₂ particles, and the ZrO₂ particles are evenly distributed in the matrix without agglomeration phenomenon. With the increase of ZrO₂ content, the density of the material decreases, the porosity increases, and the hardness tends to increase and then decrease. Under the test conditions of braking pressure of 1 MPa and rotation speed of 5 200 r/min, the friction factor and wear rate of the material decreases first and then increases with the increase of ZrO₂ content, and when the ZrO₂ addition reaches 8%, the friction and wear performance of the material reaches the best, the friction factor is 0.29, and the wear rate reaches the minimum value of 0.24 cm³/MJ.

In response to the demand for lightweight structural materials in aviation, aerospace, high-end electronics and other fields, the application of particle reinforced aluminum matrix composites has been rapidly developed. However, at present, most of the research on aluminum matrix composites focuses on the preparation and analysis of small and medium size ingot, and the research on large size ingot and its properties and microstructure is less. The hot pressing billets with the volume fraction of 15%, 20% and 25% SiCp, the matrix alloy of 2009Al and the size of ϕ580 mm×730 mm were prepared by powder metallurgy, and the extrusion rod was extruded to ϕ250 mm. The density of the extruded rods is 100%, and the particle distribution is uniform. A small amount of Al₂Cu and Al₇Cu₂Fe are found by XRD analysis. The interface between SiCp and matrix was observed by TEM. It is found that SiCp and matrix are well combined, and no harmful interfacial reaction is observed. The tensile test at room temperature shows that the strength of the composite increases significantly with the increase of the volume fraction of SiCp. When the volume fraction of SiCp is 25%, the tensile strength of the composite is 630 MPa, the yield strength is 480 MPa, and the elongation is ≥3%. The tensile strength and yield strength of the composite are 20% and 25% higher than that of the matrix, respectively. The fracture modes of the three kinds of composites with SiCp content are dominated by the ductile fracture of the matrix alloy and the fracture of SiCp, and with the increase of the volume fraction of SiCp, the fracture phenomenon of SiCp increases significantly, and the fracture is more obvious, indicating that the high strength of the interface combination of SiCp and aluminum matrix makes SiCp plays a good bearing role.