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.

Al_xCu_1-xCoFeNi high entropy alloys (x=0.25, 0.5, and 0.75) were prepared using a combination of mechanical alloying and spark plasma sintering methods. The phase composition, microstructure, and mechanical properties of the high entropy alloy powder and sintered specimens at different stoichiometric ratios were studied. The results show that the sintered Al_xCu_1-xCoFeNi high entropy alloy with a ball milling time of 64 hours forms a single face centered cubic solid solution when x=0.25 and 0.5, while the high entropy alloy forms a face centered cubic and body centered cubic solid solution structure when x=0.75. At x=0.25, 0.5, and 0.75, the densities of the sintered Al_xCu_1-xCoFeNi high entropy alloy specimens are 98.3%, 95.8%, and 97.7%, respectively. At x=0.25 and 0.5, there is segregation of Al and Cu elements in the Al_xCu_1-xCoFeNi high entropy alloy, while at x=0.75, there is segregation of Al elements and no obvious segregation of Cu elements in the high entropy alloy. As the value of x increases from 0.25 to 0.75, the yield strength, fracture strength, and hardness of Al_xCu_1-xCoFeNi high entropy alloy gradually increase, while the compressive strain gradually decreases. Compared with cast AlCuCoFeNi high entropy alloy, the yield strength, fracture strength, compressive strain, and hardness of high entropy alloy are higher at x=0.25.

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.

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.

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.

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.

Aluminum nitride ( AlN ) has become a key material in the field of electronic packaging and thermal management due to its excellent thermal conductivity, insulation and thermal expansion coefficient matching with silicon. However, AlN powder is easily hydrolyzed with water or in a humid environment to form aluminum hydroxide (Al(OH)₃) or hydroxyl alumina ( AlOOH ), resulting in the loss of nitrogen content and the increase of oxygen content, which reduces the thermal conductivity of subsequent ceramics and thermal interface material, hindering the industrial application. In this paper, the hydrolysis mechanism of AlN powder is systematically reviewed, and the regulation of various factors on the hydrolysis behavior is clarified. The surface modification technology of aluminum nitride powder is reviewed. Finally, the problems existing in the current research are pointed out, and the future development direction is prospected, which provides theoretical support and technical reference for the efficient application of AlN powder in the field of electronic devices.

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.

The energy density of traction Li-ion battery is its most important performance index. The metal lithium anode possesses ultra-high theoretical capacity (3 860 mAh/g) and ultra-low reduction potential (-3.04 V H⁺/H), and the energy density of the battery can be greatly improved by replacing the graphite anode. However, the biggest problem metal lithium anode suffer from is the electrochemical instability with the electrolyte, which result in intensified side reactions, the consumption electrolyte and the increasing the capacity decay. In addition, the growth of lithium dendrites caused by side reactions at the interface also increases the safety hazard and restricts the development of lithium metal batteries. To solve the as mentioned problems, in this study, magnetron sputtering method is used to deposit lithium phosphate (Li₃PO₄) as an artificial solid electrolyte interphase on the surface of lithium metal anode, so as to obtain high electrochemical stability of the lithium metal/electrolyte interface, and effectively inhibits the polarization of the battery. At the same time, the growth of lithium dendrites is also inhibited due to the increased lithium plating and stripping uniformity. With the modification of Li₃PO₄, which is ionic conductive and electron blocking, the time-constant mode critical circuit density increases from 1.6 mA/cm² to 3.6 mA/cm², and the capacity-constant mode critical circuit density increases from 4.0 mA/cm² to 8.6 mA/cm². The assembled pouch battery achieves an energy density of 355 Wh/kg and a capacity retention rate of 90.8% after 150 cycles at 0.2 C.

As an economic technology with the advantages of powder metallurgy and precision hot die forging, powder forging is a near-net-shape manufacturing technology, which produces parts with high precision and excellent mechanical properties by forging the preformed sintered compact. In this study, we provide a strategy to study the powder forging process as well as the mechanical properties of aluminum alloys using 6061 as an example. The constitutive equations and thermal processing maps of the sintered 6061 aluminum alloy are established through the thermal simulation, and on the basis of thermal analyses, the 6061 aluminum alloy is fabricated via powder metallurgy followed by precision hot die forging. Investigation on the microstructure and mechanical properties of as-sintered and as-forged aluminum alloys before and after T6 heat treatment are also carried out. The results show that the sintered 6061 aluminum alloy without instability during deformation in the range of 425-500 ℃/0.01-1 s^-1, indicating its excellent hot workability. Compared with the as-sintered alloys, the average grain size of as-forged alloys decreased from 12.3 μm to 9.6 μm, which enabled a uniform distribution of alloying elements. As a result, the density, hardness, yield strength and tensile strength reach 99.71%, HV64.7, 129 MPa and 220 MPa, respectively. In particular, it is noted that the as-forged alloy experienced a 138% increase in its elongation, achieving 29.6%. After T6 heat treatment, the as-forged alloys exhibit a hardness of HV135.2, a yield strength of 301 MPa, a tensile strength of 308 MPa and an elongation of 12%, and the dominant strengthening phases are composed of β" and β phases.

In order to investigate the effect of laser power on the organization and properties of iron-based alloys, iron-based alloy coatings were prepared on the surface of 45 steel using laser cladding technology, and the specimens were analytically characterized through microstructure observation, hardness experiments, and electrochemical tests to study the effect of different laser powers (1 100, 1 400, 1 700, and 2 000 W) on the organization and properties of iron-based alloy coatings. The results show that the coatings prepared with different laser powers have no defects such as porosity and cracks, and are well combined with the substrate. The phase composition of the coating mainly consists of α-Fe, γ-(Fe,Ni), α-(Fe-Cr), and γ-(Ni-Cr-Fe) phases. With the increase of laser power, the dilution rate of the coating increases, the equiaxed grains also increase gradually, and the hardness tends to increase first and then decrease. When the laser power is 1 400 W, the coating hardness is 565.4 HV0.2 at maximum, E_corr is -0.339 V at maximum, i_corr is 3.19×10^-6 A·cm^-2 at minimum, and R_ct is 71.8 kΩ at maximum, with the best corrosion resistance.

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.

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.

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%.

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.

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.

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.

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.

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.

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.

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.

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

The quality control issues associated with the reuse of titanium alloy powders in the Selective Laser Melting (SLM) technology for implantable medical devices was discussed. To address this issue, the concept of powder "circulation coefficient" is introduced, and a quantitative management method for the cyclic use of powders is established. Based on this, the physical properties, chemical composition, and mechanical properties of TC4 powders with circulation coefficients of 0, 7, and 14, and their specimens, were studied respectively. The results show that as the powder circulation coefficient increases, the performance of the powder and its prepared specimens changes in a significant, linear, and predictable manner. This verifies the feasibility and effectiveness of using the powder circulation coefficient as a quality control parameter during the recycling process of TC4 powders. Furthermore, the performance of the powder and its specimens gradually decreases during the recycling process of TC4 powders, which is related to an increase in the proportion of defective particles with excessive oxygen and nitrogen content.

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.

Additive manufacturing is an emerging material forming technology, whose shaping process is a typical non-equilibrium solidification process, involving complex physical phenomena such as temperature, thermodynamics, and phase transitions. It is difficult to measure and analyze the changes in physical quantities during the additive manufacturing process using traditional methods. Applying finite element numerical simulation technology to additive manufacturing can effectively calculate and predict the processing and outcomes, enhancing the efficiency of research and development in additive manufacturing and reducing costs. This paper provides a comprehensive review from three aspects: the finite element numerical simulation method, the introduction of finite element numerical simulation software, and their current applications in the field of additive manufacturing. It analyzes the advantages and limitations of finite element numerical simulation technology in the additive manufacturing field and offers a perspective on future development trends.

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.

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%.

The high-temperature alloy GH3536, celebrated for its exceptional thermal stability and oxidation resistance, is of paramount importance in sectors such as aeronautics and astronautics. However, conventional manufacturing techniques are limited to produce complex structural components. Thus, laser powder bed fushion (LPBF), an advanced near-net-shape manufacturing process, is increasingly recognized as a vital technology for the rapid fabrication of high-temperature alloy parts with intricate geometries. In this study, LPBF was employed to fabricate GH3536 high-temperature alloy components, and the effects of process parameters on microstructural characteristics and mechanical performance were systematically analyzed. The main phase structure of GH3536 high-temperature alloy formed by LPBF is FCC structure, accompanied by a small amount of M₂₃C₆ phase and martensitic (α) phase, with a multi-level structure of molten pool-large columnar crystals-super cellular crystals. It is also observed that upon increasing energy density, the density initially increased but subsequently decreases. The optimal processing window for GH3536 high-temperature alloy formation is identified as between 104.00 and 120.00 J/mm³, achieving a density in excess of 99.5%. Notably, at an energy density of 104.17 J/mm³, the alloy exhibited fine cellular crystal structures and high density. Under these optimal conditions, the GH3536 high-temperature alloy exhibits an exceptional combination of strength and ductility, achieving a yield strength of 649.45 MPa, a tensile strength of 854.74 MPa, and an elongation of 32.30%.

The powder of GH4698 superalloy was prepared by supreme speed plasma rotating electrode processing (SS-PREP), and a test billet was sintered by hot isostatic pressing (HIP). After the standard heat treatment, the microstructure and tensile properties of the powder metallurgy GH4698 was investigation. In this work, the mechanical properties of GH4698 superalloy prepared by SS-PREP+HIP+heat treatment route can meet the requirements of forgings. The average tensile strength at room temperature and 750 °C is 1 325 MPa and 873 MPa, respectively, which is better than cast wrought+heat treatment process. The average elongation at room temperature and 750 ℃ are 26.7% and 6.6%, respectively, which is slightly lower than that of cast wrought + heat treatment process. The average impact energy and toughness at room temperature are 60.1 J and 75.3 J/cm², respectively.

The stress and deformation of overhanging structures in laser powder bed fusion (LPBF) are critical issues for achieving high-quality and high-precision manufacturing of complex metal components. Real-time strain data measurement during the LPBF process of overhanging structures was achieved by embedding strain gauges in the substrate. Based on the in-situ strain measurement system, the strain behavior of T-shaped overhanging structures and low-angle overhangs (5° and 10°) during the LPBF process was investigated. The effects of different cantilever lengths and various process parameters on the in-situ strain behavior of T-shaped overhangs were analyzed in detail. Furthermore, the influence of different overhang angles and support types on the in-situ strain behavior of low-angle overhanging structures was analyzed. The results indicate that the longer the overhanging length of the T-shaped structure, the greater the deformation. The use of a laser energy gradient and island scanning strategy effectively reduces the deformation of T-shaped overhanging structures. Additionally, the design of the support structure significantly affects the strain behavior and forming quality of low-angle overhanging structures. The optimal forming quality is achieved using the H1 support design strategy (block support spacing of 0.8 mm and conical support spacing of 0.6 mm). These findings provide valuable insights for understanding and controlling the deformation behavior of overhanging structures in the LPBF process.

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).

Particle size is an important factor affecting the performance of hydrogen storage alloy powders, and the abnormal fluctuation of particle size will lead to the decrease of the yield of Ni-MH battery negative electrode. The factors that may affect the particle size in the process of hydrogen storage alloy powder production were verified and analyzed, especially for the dry process of alloy powders, the key parameters of powder production equipment, analysis and testing equipment and sieve mesh were verified. The results show that the abnormal particle size distribution of the products in the pulverizing process has no obvious correlation with the pulverizing equipment and testing equipment, and the main cause of particle size problem is the deviation of wire diameter of screen used in pulverizing, and effective control measures are formulated accordingly.

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.

To investigate the influencing factors of crack formation and the wear mechanism of Fe₃Al/Cr₃C₂ composites, orthogonal experiments were conducted by laser cladding Fe₃Al/Cr₃C₂ composite coatings on carbon structural steel substrates. The coatings were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and wear tests. The results show that among the factors affecting crack formation in the cladding layer, the Cr₃C₂ content is the most critical. Coatings with 15% and 25% Cr₃C₂ exhibit the fewest cracks. In terms of wear resistance, these same coatings also display the lowest wear rates, which can be attributed to their reduced tendency for adhesive wear and the refined microstructure of the reinforcing phases that facilitate surface separation during abrasion. The morphology and distribution of the reinforcing phases in the cladding layer play a crucial role in wear resistance. During friction, the softer Fe₃Al matrix wears away first, while the harder carbides support the worn surface and reduce friction. As wear progresses, the carbides gradually disappear from the surface and transform into hard phase particles.

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.

The gas flow field of electrode-induced melting gas atomization technology was simulated using the FLUENT software for fluid dynamics. The influence of supersonic nozzle on different inlet pressures (2, 3, 4 MPa), angles (40°, 45°, 50°), and distances (12, 18, 22 mm) between the supersonic nozzle outlet and metal flow were analyzed. The results indicate that the gas flow field exhibits a series of expansion wave and compression wave jet structures. Increasing the injection pressure effectively enhances the velocity of the gas jet and theoretically generates greater shear force to facilitate atomization. Proper adjustment of the nozzle angle minimizes pressure loss between the gas and pipe wall while controlling the position of the return gas field. Additionally, the distance between nozzle outlet and metal liquid flow affects the location of reflux gas field. As this distance increases, there is a gradual reduction in speed as well as convergence into reflux gas field before being far away from nozzle outlet. If reflux gas field is near center hole (liquid flow down channel) of nozzle, it hinders downward liquid flow leading to reverse injection and splashing. Conversely, if return gas field is far from center hole of nozzle, insufficient atomization occurs resulting in coarse powder particles with irregular shapes.

The diamond/Ni-Cu composite specimens which can be used in the carcass of polycrystalline diamond compact (PDC) drills were successfully prepared by using electron beam selective melting (EBSM) technology, and the effects of diamond volume fraction on the density, flexural strength, wear resistance and erosion resistance of diamond/Ni-Cu composites were systematically investigated. The results indicate that with the increase of diamond volume fraction, the density and flexural strength of diamond/Ni-Cu composite samples generally show a trend of first decreasing, then entering a relatively stable stage, and then rapidly decreasing. However, the wear ratio of diamond/Ni-Cu composites specimens shows a trend of increasing first and then rapidly decreasing when the volume fraction of diamond increases from 10% to 35%, and the wear ratio reaches the maximum value of 1.08 when the volume fraction of diamond is 25%. However, the erosion mass loss of the diamond/Ni-Cu composite specimens shows a trend of first decreasing and then increasing as the volume fraction of diamond gradually increases from 10% to 35%. When the weight loss reaches the minimum value of 7.50 mg, the volume fraction of diamond is 25%. Therefore, when the diamond volume fraction is 25%, the wear resistance and erosion resistance of the diamond/Ni-Cu composites prepared by EBSM are optimized simultaneously.

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.