【Objective】 In response to the application requirements of additive manufacturing (AM) technology for metallic lattice-structured components, this paper clarifies the key technical points and research progress of AM in fabricating metallic lattice structures, investigates the critical issues in the forming, property regulation and defect control of such components, and provides theoretical references and research insights for the technological development and engineering application of additively manufactured metallic lattice-structured components.
【Method】 Using literature investigation and comprehensive analysis, this work systematically reviewed the development history and application status of additively manufactured metallic lattice-structured components, focused on the classification and characteristics of lattice structures, and expounds the technical advantages of additive manufacturing for fabricating lattice structures. From a metallurgical perspective, the dynamic process of powder melting and solidification during the lattice structure forming procedure was analyzed, the regulation mechanism of heat treatment on the mechanical properties of the components was investigated, the defect formation mechanisms of metallic lattice structures was comprehensively summarized, and the mainstream defect detection methods at the current stage was sorted out.
【Result】 The structural characteristics and differences in mechanical properties of three types of lattice structures (truss-type, triply periodic minimal surface (TPMS), and bionic-type lattices) are clarified. Additive manufacturing is confirmed to exhibit prominent advantages in the fabrication of metallic components with complex lattice structures, such as high design flexibility, large forming freedom, and the ability to realize the synergistic optimization of lightweight and performance. The influence laws of micro-melt pool characteristics, remelting phenomena and process parameters on the forming quality of lattice structures are revealed. The coupling relationships between heat treatment processes, microstructures and mechanical properties of lattice structures with different matrix materials are analyzed. The common defects and corresponding formation mechanisms of additively manufactured metallic lattice-structured components are summarized, and industrial computed tomography (CT) integrated with intelligent algorithms is identified as an efficient approach for the defect detection of lattice structures at the current stage.
【Conclusion】 Additive manufacturing provides an effective approach for the fabrication of complex metallic lattice structures. Benefiting from the advantages of high specific strength, high specific stiffness, lightweight and multifunctionality, metallic lattice‑structured components present broad application prospects in aerospace, medical treatment, automotive engineering and other fields. Among these aspects, the regulation of the melting and solidification process during additive manufacturing, the optimization of heat treatment processes, and defect detection and control are the key links to improve the forming quality and performance of additively manufactured metallic lattice‑structured components. For the future development of additive manufacturing technology for metallic lattice‑structured components, efforts should be focused on the multi‑scale optimal design of lattice structures, the investigation of the metallurgical essence of additive manufacturing, the construction of the full‑cycle manufacturing process, and the full exploitation of AM technical advantages, so as to promote the engineering application of this technology in high‑end equipment manufacturing and other fields.

【Objective】 This study aims to solve the manufacturing challenges of traditional processing for complex heat sinks, including difficult forming, low material utilization, and high production costs. The work focuses on developing a low-cost preparation route for complex pure copper heat sinks based on water-atomized copper powder. The research intends to explore the effects of powder loading, feedstock rheological behavior, and to establish a stable and reliable process window for mass production and provide technical support for the near-net-shape manufacturing of high-performance metal heat dissipation parts.
【Method】 Low-cost water-atomized copper powder with near-spherical morphology was selected as the raw material, and pure copper heat sinks were fabricated via powder injection molding. The rheological properties of different feedstocks and the sintering densification rules of green bodies were systematically investigated in the experiments. A hydrogen atmosphere was adopted to promote the full densification of pure copper compacts after injection molding and debinding. After sample preparation, the thermal conductivity and electrical conductivity of sintered components were quantitatively tested. The differences in comprehensive performance under various process conditions were compared and analyzed to determine the optimal fabrication parameters.
【Result】 Under the optimized condition of hydrogen sintering at 1 070 °C for 3 hours, the powder injection molded pure copper heat sink shows a dense and uniform internal microstructure with complete forming quality and no obvious internal defects. The measured thermal conductivity reaches 373 W/(m·K), which provides excellent heat dissipation capability for high-heat-load service environments. Meanwhile, the electrical conductivity maintains 90.5% IACS, which reflects good metallurgical bonding quality and stable overall service performance of the sintered pure copper components.
【Conclusion】 Powder injection molding exhibits excellent process adaptability for preparing complex pure copper heat sinks and achieves low-cost production with high material utilization. The optimized injection, debinding, and hydrogen sintering processes effectively improve densification degree and thermoelectric performance, and successfully overcome the shortcomings of traditional mechanical processing. The manufactured pure copper heat sinks have excellent thermal and electrical properties and fully satisfy the high-efficiency heat dissipation requirements of precision instruments, new energy vehicles, and high-speed rail equipment. This optimized process provides a reliable industrial production strategy for the batch manufacturing of high-performance complex heat dissipation components.

【Objective】 Zirconia ceramics are widely used in electronics, biomedical devices, and other fields due to their excellent mechanical properties, as well as good wear and corrosion resistance. However, their conventional fabrication processes still face challenges: traditional injection molding is limited by the low debinding efficiency of paraffin‑based binders, while the poor flowability of powders in conventional compression molding makes it difficult to form complex parts. Polyoxymethylene (POM)‑based binders exhibit superior comprehensive performance, enabling efficient debinding and reduced deformation, thus providing a new approach to solving ceramic forming issues. This study develops a POM‑based zirconia ceramic feedstock suitable for compression molding, and investigates feedstock preparation, process optimization, debinding, sintering, and application, aiming to provide an important technical basis for high‑quality industrial production of zirconia.
【Method】 Using 3 mol% Y₂O₃‑stabilized zirconia powder (3Y‑TZP) as the raw material, the 3Y‑TZP powder and a POM‑based binder were mixed at a volume ratio of 1∶1 in an internal mixer (180 ℃ for 2 h). The mixture was then mechanically crushed and sieved through a 60‑mesh screen to obtain fine‑particle feedstock with particle size ≤0.25 mm. Green compacts of dimensions 30 mm × 12 mm were formed by warm compression molding under different mold temperatures, holding times, and pressing pressures. The green compacts were subjected to catalytic debinding under different debinding media (oxalic acid, nitric acid debinding furnace), temperatures (110, 120, 130 ℃), and times (1, 3, 5, 7 h). The debound samples were sintered in a box furnace at sintering temperatures (1 400, 1 450, 1 500, 1 550, 1 600 ℃) and holding times (1, 2, 3, 4 h). The optimal process parameters for compression molding, catalytic debinding, and sintering were systematically investigated, and the microstructure and mechanical properties of the final zirconia products were characterized.
【Result】 Warm compression molding experiments of the POM‑based feedstock showed that the green density first increased and then decreased with increasing mold temperature, holding time, and pressing pressure. Under the conditions of mold temperature 180 ℃, holding time 10 min, and pressing pressure 80 MPa, the green density reached 3.51 g/cm³, with a dense and uniform cross‑section. Feedstock with a high binder content achieved high‑density zirconia ceramics during the sintering stage when warm‑compacted. In contrast, compression molding at room temperature could not yield high density after sintering. Catalytic debinding in a nitric acid atmosphere at 120 ℃ for 5 h resulted in almost complete removal of the POM binder from the green compacts. With increasing sintering temperature and holding time, grain size and volumetric shrinkage continuously increased, while relative density and mechanical properties first improved and then slightly decreased. Sintering at 1 500 ℃ for 2 h was identified as the optimal condition: the material exhibited t‑ZrO₂ as the main phase, a uniform and dense microstructure with no obvious pores or defects, a relative density of 99.1%, Vickers hardness of 1 384.53HV, and flexural strength of 1 073.25 MPa.
【Conclusion】 This study employs warm compression molding of a POM‑based zirconia ceramic feedstock, overcoming the problems of insufficient powder flowability and difficulty in forming complex parts associated with conventional room‑temperature compression molding, and reveals the fundamental rules of forming and sintering. Furthermore, the developed warm compression molding process using the POM‑based binder for 3Y‑TZP provides a basis for low‑cost, high‑efficiency compression molding of high‑performance complex zirconia ceramics.

【Objective】 The demand for magnets with high remanence and high coercivity in the market continues to grow, and grain refinement technology serves as a key approach to achieve rare-earth-free magnets with both high remanence and high coercivity.
【Method】 This study employed an alloy with a nominal composition of Nd_30.8Fe_balCoAl_0.5Cu_0.1B and adjusted the average particle size of fine powders by varying the classifier wheel speed during jet milling.
【Result】 As the classifier wheel speed increases from 3 000 r/min to 5 500 r/min, the powder particle size decreases from 3.41 μm to 2.34 μm. In terms of magnetic performance, the magnet derived from 2.34 μm powder exhibits the highest coercivity, while the 2.47 μm powder sintered magnet demonstrates the maximum remanence. The ranking of apparent density, tap density, and forming density for the six powder particle sizes aligns with their size order—larger particles correspond to higher apparent and tap densities, and vice versa. However, sintered density relates to the optimal densification temperature for different particle sizes, with the 2.47 μm powder achieving the highest post-sintering density. Orientation degree data reveals that under uniform sintering conditions, finer powder particle sizes lead to reduced orientation.
【Conclusion】 In the process design of grain refinement for sintered NdFeB magnets, factors such as formability, sintered density, and orientation degree must be prioritized alongside oxidation prevention.

【Objective】 This study aims to use the Cu₂₉La₇₁ alloy as a diffusion source to improve the coercivity (H_cj) of HDDR NdFeB magnetic powder through diffusion heat treatment.
【Method】 The Cu₂₉La₇₁ alloy was prepared by vacuum arc melting, followed by low-speed ball milling to mix the alloy powder with HDDR NdFeB magnetic powder. Bonded magnets were then fabricated via vacuum diffusion heat treatment. The influence and mechanism of Cu₂₉La₇₁ alloy and heating process on the H_cj, remanence (B_r) and maximum magnetic energy product (BH_max) of magnetic powders were investigated.
【Result】 The H_cj of the bonded magnets first increased and then decreased with rising diffusion temperature and Cu₂₉La₇₁ addition. The maximum H_cj of 923 kA/m was achieved at an optimal diffusion temperature of 380 ℃ with 0.5 wt.% Cu₂₉La₇₁ addition, representing an 11.88 % improvement over the non-diffusion magnets (825 kA/m). The highest B_r (0.583 T) and BH_max (53 kJ/m³) were obtained with 1.0 wt.% alloy addition at 380 ℃, corresponding to increases of 10.21 % and 20.45 % compared to the non-diffusion magnet (0.529 T, 44 kJ/m³). Microstructural analysis confirmed that La diffused along grain boundaries into the NdFeB particles during heat treatment.
【Conclusion】 Grain boundary diffusion with low-cost Cu₂₉La₇₁ alloy effectively enhances the H_cj and B_r of HDDR NdFeB powders. The performance improvement is governed by two competing mechanisms: the beneficial diffusion of La along grain boundaries repairs defective regions surrounding Nd₂Fe₁₄B grains, forming the La₂Fe₁₄B phase which improves H_cj and B_r of the magnetic powder. Conversely, excessive diffusion temperature or alloy addition promotes volume diffusion of La into the Nd₂Fe₁₄B lattice, where substitution of Nd sites by La degrades the magnetic properties. Furthermore, since Cu₂₉La₇₁ is a non-magnetic phase, excessive alloy addition reduces the B_r and BH_max. Consequently, the optimal magnetic performance is achieved at a diffusion temperature of 380 ℃ with an alloy content in the range of 0.5-1.0 wt.%.

【Objective】 Selective laser melting (SLM) technology is an effective method for fabricating parts with complex structures, and single-pass is the basic unit for fabricating parts. The surface morphology and geometric dimensions of W-25Re alloy single-pass are analyzed in order to explore the process parameter windows of SLMed single-pass and provide reference for the subsequent fabrication of high-quality W-25Re alloy parts.
【Method】 The spherical W-25Re alloy (mass fraction, %, the same below) powder was used as raw material to study the effects of laser power, scanning speed and substrate material on the surface morphology and geometric dimensions of the W-25Re alloy single-pass during the SLM processing. In order to avoid the influence of accidental factors on the test results, five single-pass were printed for each set of experimental parameters.
【Result】 The forming quality of W-25Re alloy single-pass with W-25Re alloy substrate is higher than with pure W substrate with laser power of 150~250 W and the scanning speed of 200~800 mm/s. Using W-25Re alloy substrate, the width of the W-25Re alloy single-pass increases with the increase of laser power, while the width of the single-pass decreases with the increase of scanning speed. When the laser power is 250 W and the scanning speed is 200 mm/s, the single-pass width is the largest, up to 196.9 μm, which is much larger than the laser spot diameter of the equipment. The standard deviation coefficients of the single-pass width are all <5%. The stability of the single-pass width is good. The single-pass width y and the linear energy density x have an obvious linear relationship, the relationship between the two is y=103.29x+73.44.
【Conclusion】 The laser power, scanning speed and substrate material significantly affect the morphology of the molten pool of W-25Re alloy single-pass. Based on the relationship between the width of single-pass and the linear energy density, together with the standard deviation coefficient, it is possible to predict the width and stability of single-pass. This provides guidance for the selection of process parameter windows in practical experiments.

【Objective】 Selective laser melting (SLM) is an emerging manufacturing technique. Meanwhile, ZrB₂ is considered as an ideal reinforcing phase to enhance the wear resistance of aluminum (Al) alloys in the conventional preparation process. However, the effect of ZrB₂ on the wear resistance of SLM Al alloys is still unclear. Therefore, it was necessary to investigate the role of ZrB₂ on the wear performance of the SLM‑AlSi10Mg alloy and to reveal its underlying mechanism under SLM forming conditions.
【Method】 The microstructures, mechanical properties, and friction and wear behaviors under different loads (1~15 N) of SLM‑AlSi10Mg and SLM‑ZrB₂/AlSi10Mg were compared and analyzed, and the mechanism by which ZrB₂ affects the friction and wear behavior of SLM‑AlSi10Mg is revealed.
【Result】 ZrB₂ has no significant effect on the microstructure of SLM-AlSi10Mg, but increases the hardness and yield strength of 31.5HV_0.05 (121.3→152.8HV_0.05) and 45.0 MPa (240.0→285.0 MPa) as well as reduce the elongation of 0.6% (7.3%→6.7%) for its high hardness .The relative wear resistance of SLM-ZrB₂/AlSi10Mg to SLM-AlSi10Mg gradually increased from 1.03 at 1 N to 1.10 at 6 N, and then sharply rose to 1.34 at 9 N and 1.46 at 15 N. The dominant wear mechanism for both aluminum alloys under loads ranging from 1 to 15 N is abrasive wear.
【Conclusion】 The micro-cutting behavior of 304L steel balls could be effectively hindered by ZrB₂ particles due to their high hardness and excellent bonding with the Al matrix. Therefore, the wear resistance of SLM-ZrB₂/AlSi10Mg is better than that of SLM-AlSi10Mg. Especially, the contact stress exceeds the critical contact stress for plastic flow to occur in the 304L steel balls at loads≥9 N, resulting in a significant increase in the tribolayer hardness of the steel ball wear. The increasing tribolayer hardness exacerbates the micro-cutting behavior of the steel balls on the Al alloy and amplifies the hindering effect of the ZrB₂ particles on its micro-cutting behavior. As a result, the wear volume as well as the relative wear resistance dramatically increase with the increasing load from 6 N to 9 N.

【Objective】 With the rapid iteration of high frequency communication and microelectronic devices, printed circuit boards （PCB） have shown characteristics of high density and refinement. The precuring and low temperature sintering processes of nano-copper paste have a significant impact on the interconnection performance of high density PCB. However, the existing studies mainly focused on the sintering process and lacked systematic research on the precuring process parameters.
【Method】 Therefore, this paper, based on constant temperature and pressure differential thermogravimetry analysis, investigated the influence laws of parameters such as precuring temperature, gas pressure and time on the surface microstructure and sintered body properties of interconnect nano-copper paste.
【Result】 The results show that during the pressure reduction prefixation process, the pressure difference between the inside and outside of the copper paste drives the diffusion of the organic carrier. When the diffusion rate is greater than the evaporation rate controlled by the precuring temperature, the organic carrier accumulates on the surface, and after evaporation, depressions are formed on the precuring solid surface. In the normal pressure precuring process, the surface carriers are preferentially evaporated to form a drying layer and generate residual stress. The stress accumulates continuously and eventually leads to surface cracking. The precuring solid with the fewest surface defects exhibits the best sintered body performance.
【Conclusion】 This paper reveals the influence law of precuring conditions on the formation of surface defects on the precuring solid, which can provide theoretical support and practical guidance for the high performance application of nano-copper paste in high density PCB.

【Objective】 This paper aims to study the evolution of carbides and borides in the fourth-generation powder metallurgy (PM) superalloy FGH4102 after long-term aging at 750~850 ℃. The objective is to clarify the thermal stability of carbides and borides within the service temperature range, and provide reference for the service application of turbine disks.
【Method】 The FGH4102 alloy was subjected to a solution treatment at 1 180 ℃ for 2 h, followed by oil quenching, and then an aging treatment at 815 ℃ for 16 h, followed by air cooling. Specimens in the heat-treated condition were subsequently subjected to long-term aging at 750 ℃, 800 ℃, and 850 ℃. The maximum aging durations were 3 000 h at both 750 ℃ and 800 ℃, and 2 000  h at 850 ℃.Thermodynamic calculations of equilibrium phase precipitation in the alloy were performed using the JMatPro software with the corresponding nickel‑based superalloy database. The evolution of carbides and borides during both the preparation process and long‑term aging was characterized by optical microscopy (OM), JSM‑7800F field‑emission scanning electron microscopy (SEM), JXA‑8530F field‑emission electron probe microanalysis (EPMA), and Tecnai G2 20 transmission electron microscopy (TEM).
【Result】 Microstructural characterization of the heat-treated FGH4102 alloy reveals that, in addition to the γ matrix and γ' precipitates, the primary minor phases are MC-type carbides and M₃B₂-type borides, which is generally consistent with thermodynamic calculations. After heat treatment, MC carbides are predominantly distributed as fine particulates dispersed throughout the matrix, exhibiting good thermal stability after prolonged high-temperature aging. Following forging, M₃B₂ borides are randomly distributed as granular particles within the matrix. After solution heat treatment, M₃B₂ particles are mainly located at grain boundaries with relatively fine sizes. Upon long-term aging, these M₃B₂ borides form a chain-like structure along the grain boundaries.
【Conclusion】 The FGH4102 alloy demonstrates favorable carbide stability following long-term thermal exposure. Meanwhile, borides precipitate as chain-like networks along grain boundaries, which effectively enhances the alloy's stress-rupture and creep resistance at elevated temperatures. These findings offer meaningful insights for the future compositional optimization and engineering application of the alloy.

【Objective】 This study aims to fabricate SiO₂-hybridized reduced graphene oxide (rGO)-reinforced copper matrix composites using spark plasma sintering (SPS), and to systematically investigate their microstructure characteristics and tribological properties, with particular attention to the synergistic effects of nano- SiO₂ and rGO on friction and wear behavior.
【Method】 The composites were prepared via a wet mixing process to achieve uniform adsorption of nano-SiO₂ particles onto rGO sheets, followed by densification using SPS under the conditions of 750 °C, 45 MPa, and 8 min. The microstructure of mixed powders and sintered composites was characterized, and tribological tests were conducted under varying applied loads and nano-SiO₂ contents to evaluate the coefficient of friction (COF) and wear rate.
【Result】 Observations confirm that the wet mixing process enables uniform dispersion of nano-SiO₂ on rGO surfaces. After SPS, the composites exhibite a multiscale structure with rGO sheets intercalate by numerous nano-SiO₂ particles, uniformly distribute within the copper matrix. Tribological tests show that as the applied load increases, the COF decreases while the wear rate increases. Raising the nano-SiO₂ content simultaneously reduces the COF and markedly improves wear resistance. The hybridized nano-SiO₂ particles and rGO nanosheets act synergistically to enhance the anti-wear capability of the material.
【Conclusion】 SPS-fabricated SiO₂-hybridized rGO/Cu composites exhibit a favorable multiscale microstructure, in which nano-SiO₂ reduces friction and significantly boosts wear resistance. The synergistic interaction between nano-SiO₂ and rGO is key to this enhanced tribological performance, making the composites highly promising for low-friction, high-durability applications.

【Objective】 This study aimed to investigate the application performance of ultrafine iron powder in the matrix of diamond thin-walled drill bits. The optimal mass fraction of ultrafine Fe powder, diamond concentration and sintering temperature were explored to optimize the comprehensive service performance of drill bits.
【Method】 Drilling performance tests were conducted on drill bit matrices with ultrafine Fe powder mass fractions of 30%, 40% and 50%. Comparative cutting experiments were implemented at diamond concentrations ranging from 35% to 50%. In addition, the drilling and cutting properties of drill bits sintered at four temperature gradients of 925, 935, 945 and 955 ℃ were systematically compared and analyzed.
【Result】 The matrix containing 40% ultrafine Fe powder exhibits superior drilling efficiency yet a shorter service life, while the matrix with 30% ultrafine Fe powder delivers a longer service life at the expense of reduced drilling efficiency. Within the tested concentration range of 35%-50%, a diamond concentration of 45% achieves both enhanced cutting efficiency and prolonged cutting life. Reasonable sintering temperature and resultant sintering density effectively regulate the working state of diamond abrasives.
【Conclusion】 The optimal combination of ultrafine Fe powder proportion, diamond concentration and sintering temperature guarantees the wear resistance of the drill bit matrix, which effectively improves the overall drilling life and working efficiency of diamond thin-walled drill bits.

【Objective】 The objective of this study was to investigate the effect of Fe₃Al particle size on the friction and wear properties of copper‑based powder metallurgy friction materials, aiming to identify the optimal particle size for high‑speed railway braking applications.
【Method】 Copper based friction materials were fabricated via powder metallurgy. The matrix consisted of Cu, Sn, and Fe powders, the friction components were Cr Fe and Fe₃Al, and MoS₂ and graphite served as lubricants. Five groups of specimens were prepared with Fe₃Al particle sizes of 106, 74, 58, 48, and 45 µm. The powders were weighed according to the designed compositions, mixed in a V type blender for 3.5 h, and then cold pressed at 600 MPa for 45 s. Sintering was performed at 950 ℃ in an argon atmosphere for 2.5 h. The density and hardness of the sintered materials were measured using the Archimedes method and a Brinell tester, respectively. Friction and wear tests were conducted on a tribometer at five braking speeds (150~350 km/h), with each test repeated 10 times and averaged. Wear loss was determined by weighing, and the worn surface microstructures were observed using scanning electron microscopy.
【Result】 The results show that both the hardness and density of the sintered materials first increase and then decrease as the Fe₃Al particle size decreases, reaching their maximum values at 58 µm. The friction coefficient exhibits an overall increasing trend with decreasing particle size, and at 58 µm the material maintains a relatively high friction coefficient across all tested braking speeds. At low braking speeds, the particle size has only a minor effect on the wear rate, however, when the speed exceeds 300 km/h, the material with 58 µm Fe₃Al particles displays a higher friction coefficient and a lower wear amount compared to other sizes. Furthermore, as the Fe₃Al particle size decreases, the dominant wear mechanism on the friction surface gradually transitions from fatigue wear to abrasive wear, and finally to adhesive wear.
【Conclusion】 It is concluded that the Fe₃Al particle size significantly influences the physical and tribological properties of copper‑based friction materials. The optimal particle size of 58 µm provides the best combination of high density, hardness, and friction stability, while also ensuring low wear under high‑speed braking conditions. The observed wear mechanism transition suggests that finer particles tend to cause more severe interfacial damage, which may degrade the material’s durability at extreme speeds. Therefore, for high‑speed railway applications, Fe₃Al particles with a size around 58 µm are recommended for achieving reliable and long‑lasting braking performance.

【Objective】 Copper (Cu) powders are widely used as conductive fillers in microelectronics due to their excellent electrical conductivity and low cost. However, the practical application of Cu powder is severely hindered by its high susceptibility to oxidation at elevated temperatures, leading to increased resistivity and device failure. Silver (Ag) coating is an effective strategy to enhance antioxidation properties while maintaining high conductivity. This study aims to fabricate core-shell structured Cu@Ag composite powders via electroless plating and systematically investigates the influence of preparation parameters on the microstructure and comprehensive performance of the powders.
【Method】 The core-shell Cu@Ag composite powders were successfully prepared using a chemical plating method. The phase composition, surface morphology, elemental distribution, and thermal stability of the synthesized powders were thoroughly characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and thermogravimetric analysis (TGA). Furthermore, an oxidation reaction kinetics model was established to elucidate the oxidation mechanism of the coated powders.
【Result】 The results indicate​ that optimized process parameters significantly affect powder properties. Under the conditions of 30% Ag content, 50 ℃ reaction temperature, 0.16 mol/L glucose concentration, and 300 W ultrasonic power, the obtained Cu@Ag powders exhibit​ a uniform and dense silver shell. Compared to pure Cu counterparts, these optimized powders demonstrate​ superior electrical conductivity and enhanced antioxidation performance. Specifically, the initial oxidation temperature of the core-shell powders reaches​ approximately 230 ℃, representing a significant improvement. Kinetic analysis reveals​ that the oxidation process follows a 1/3 order chemical reaction and conforms​ to the shrinking cylinder kinetic model controlled by a phase-boundary reaction, indicating that the Ag shell effectively acts as a physical barrier to oxygen diffusion.
【Conclusion】 This work provides​ a reliable approach for preparing high-performance Cu@Ag composite powders with excellent antioxidation properties. The establishment of the kinetic model offers​ theoretical guidance for understanding the oxidation mechanism and predicting the service life of Cu-based conductive materials in high-temperature environments.

【Objective】 Ball mills are common equipment for material mixing, but multi-component fine particle mixing uniformity is restricted by various parameters. Previous researches mostly focused on binary particle systems, so this study explored how six technological and structural parameters affected the mixing performance of boron, silicon, charcoal and jujube wood medium particles, and sought out the optimal parameter combination.
【Method】 A six-factor three-level orthogonal experiment was designed. The discrete element software Rocky-DEM was used to build the simulation model, and the Hertzian Spring Dashpot model was adopted to simulate particle collisions. The coarse-grained model was applied to process fine particles and revise contact parameters. Lacey Mixed Index (LMI) served as the evaluation index. Visual observation and variance analysis were conducted to analyze test results, and physical experiments were carried out for verification.
【Result】 Seepage effect led to axial stratification between medium balls and raw particles in some groups. Filling rate had the greatest influence on mixing uniformity, followed by partition plate number and rotational rate. Medium ball diameter, ball-material ratio and mixing time had insignificant effects. The optimal parameters were 65% rotational rate, 15 mm ball diameter, ball-material ratio of 1.25, 8 partition plates, 15 s mixing time and 10% filling rate. The mean absolute error between simulation and experimental data was 3.72%.
【Conclusion】 Rotational rate, filling rate and partition plate number are key factors affecting particle mixing. The optimized parameter combination can effectively improve mixing uniformity and reduce particle stratification. The simulation and test method adopted in this study is reliable, and the results can guide the practical operation and parameter optimization of ball mills.

【Objective】 To address the bottlenecks of difficult activation, sluggish absorption/desorption kinetics, and poor cyclic stability in traditional solid-state hydrogen storage materials, this study aimed to design and validate a novel AB₂-type high-entropy alloy (HEA), TiZrCrMnFeNi, with a predominant C14 Laves phase. The objective was to systematically investigate its macroscopic hydrogen storage performance, particularly room-temperature kinetics and cycling lifespan, alongside its microscopic crystal structure, electronic structure, and interfacial adsorption mechanisms.
【Method】 Thermodynamic phase diagrams were calculated using Thermo-Calc software to guide the compositional design. The TiZrCrMnFeNi alloy samples were synthesized via vacuum arc melting and subsequent annealing at 600 ℃. The phase composition and crystallographic features were characterized using X-ray diffraction (XRD) with GSAS Rietveld refinement and electron backscatter diffraction (EBSD). The room-temperature hydrogen absorption/desorption kinetics and cycle life were evaluated using a Sieverts-type pressure-composition-temperature (PCT) apparatus. Furthermore, first-principles calculations based on density functional theory (DFT) were performed using the VASP package. The ground-state supercell structure was optimized, and the density of states (DOS), surface energies of different low-index facets, and hydrogen adsorption energies were calculated.
【Result】 XRD and EBSD refinements confirm that the synthesized TiZrCrMnFeNi alloy consists of a predominant C14 Laves phase (> 95%) and a minor body-centered cubic (BCC) phase. The lattice parameters of the C14 phase optimized by DFT show only a 1% deviation from the experimental measurements, which verifies the accuracy of the theoretical model. The alloy exhibits exceptional room-temperature hydrogen storage kinetics without the need for prior activation. At 300 K, it reaches over 80% of its maximum capacity within 1 minute and achieves a saturated absorption capacity of 1.65 wt.% (forming TiZrCrMnFeNiH₆) within 2 minutes. The desorption process is reversible within 3 minutes with a capacity of 1.62 wt.%. Furthermore, the alloy displays excellent cyclic stability, with no significant capacity degradation after 500 complete absorption/desorption cycles. The total DOS exhibits spin asymmetry, and the electronic states near the Fermi level are primarily dominated by the 3 d orbitals of Ni, Fe, Ti, and Mn, displaying distinct orbital degeneracy. Surface thermodynamic calculations indicate that the (111) facet possesses the lowest surface energy, demonstrating the highest structural stability. Meanwhile, the (110) facet exhibits the lowest hydrogen adsorption energy, identifying it as the optimal thermodynamic pathway for H2 chemisorption, dissociation, and subsequent interstitial diffusion.
【Conclusion】 The detailed experimental and theoretical results demonstrate that rational high-entropy compositional design effectively stabilizes the C14 Laves solid-solution phase with high hydrogen storage activity. The TiZrCrMnFeNi high-entropy alloy possess the advantages of fast room-temperature kinetics, high reversibility, and an exceptionally long cycle life. These characteristics highlight its significant engineering application potential in solid-state hydrogen storage. Moreover, the elucidated atomic-scale interfacial mechanisms reveal that the (111) plane provides the structural framework stability, while the (110) plane governs the catalytic and adsorption activities, offering a robust scientific foundation for future performance optimization via interface engineering or preferred crystallographic orientation.

【Objective】 Molybdenum-copper (Mo-Cu) composites integrate the high melting point, high strength and low thermal expansion of molybdenum with the outstanding electrical and thermal conductivity of copper, and are widely applied in electronic heat sinks, electrical contactors and aerospace high-temperature structural components. Traditional fabrication routes including liquid-phase sintering and infiltration suffer from low relative density, uneven copper infiltration and abundant interfacial pores, which severely degrade the comprehensive performance of Mo-Cu products. Hot isostatic pressing (HIP) can produce near-full-density powder metallurgy components under coupled high temperature and high pressure, yet systematic research on HIP-manufactured Mo-Cu alloys with varied copper fractions remains insufficient. This work aims to fabricate three HIP-processed Mo-Cu alloys with 30 wt%, 40 wt% and 50 wt% copper, systematically reveal the regulation mechanism of copper content on densification, microstructure, electrical, mechanical and thermophysical properties, and provide experimental data and compositional design reference for high-performance HIP Mo-Cu composites used in electronic packaging and thermal management fields.
【Method】 High-purity molybdenum powder (99.95% purity, 2.8-3.5 μm) and electrolytic copper powder (99.9% purity, 45 μm) were adopted as raw materials. Powder mixtures with mass ratios of Mo∶Cu = 70∶30, 60∶40 and 50∶50 were blended in a 3D mixer for 6 h, compacted into green bodies and sealed in stainless steel cans after vacuum degassing. HIP treatment was carried out at 1 000 ℃, 180 MPa for 2 h with furnace cooling. Multiple characterization and testing methods were conducted: Archimedes’ principle for bulk density and relative density, optical metallographic microscope to observe two-phase distribution, eddy current conductivity tester for room-temperature electrical conductivity, universal testing machine following GB/T 228.1-2021 for tensile mechanical properties, dilatometer (25-800 ℃, Ar atmosphere) to test linear thermal expansion coefficient, laser flash apparatus to measure thermal diffusivity, and thermal conductivity was calculated via the formula λ=α·Cp·ρ.
【Result】 All HIP specimens reached nearly full densification with relative densities ranging from 99.7% to 100.2%, eliminating the intrinsic porosity defects of conventional sintered Mo-Cu. Metallographic observations show discrete Cu islands filling gaps between Mo particles, and the area fraction of Cu phase rises with increasing copper content, accompanied by slight local agglomeration of Mo and Cu phases caused by powder mixing limits. As copper content increases from 30 wt% to 50 wt%, electrical conductivity monotonically rises from 46.36% IACS to 59.88 %IACS, benefiting from high densification that reduces electron scattering at pores. Tensile strength and yield strength decrease continuously from 575 MPa and 379 MPa (Mo-30Cu) to 442.5 MPa and 301.5 MPa (Mo-50Cu), while fracture elongation and reduction of area grow steadily, demonstrating improved ductility at higher Cu fractions. Linear thermal expansion coefficient increases with copper content and temperature, and its growth rate accelerates above 500 ℃ due to weakened constraint from continuous Mo matrix. Thermal diffusivity increases monotonically with copper addition, while specific heat capacity rises first then falls, thermal conductivity peaks at 243.1 W/(m·K) for Mo-40Cu, and declines slightly at 50 wt% Cu because excessive Mo-Cu phase interfaces aggravate free electron scattering.
【Conclusion】 HIP technology is an effective route to prepare near-full-density Mo-Cu composites and overcomes the uneven infiltration and low densification drawbacks of traditional sintering techniques. Copper mass fraction acts as a core factor to balance the electrical, mechanical and thermophysical performances of Mo-Cu alloys: low-Cu formulations feature high strength and low thermal expansion, while high-Cu grades deliver superior conductivity and ductility. Mo-40Cu alloy exhibits optimal comprehensive thermal conductivity and balanced mechanical properties, which is the preferred candidate for high-power chip heat sinks and electronic packaging materials. Minor phase segregation originating from powder mixing restricts microstructure uniformity, and further optimization of mixing procedures can be implemented in follow-up research. This study establishes a complete property database for HIP Mo-Cu alloys and provides guidance for component selection in electronic, aerospace and chemical industrial applications.

【Objective】 To mitigate environmental pollution caused by excessive antibiotics, there is an urgent need to develop novel technologies for antibiotic wastewater treatment that feature strong oxidation capacity, mild operating conditions, low preparation costs, non-toxicity, zero secondary pollution, and superior photocatalytic performance.
【Method】 TiO₂ nanoparticles supported on fly ash cenospheres were prepared by using titanium butoxide as titanium source and fly ash cenosph as carrier. The surface micromorphology and physical characteristics of the prepared composite photocatalysts were characterized and analyzed via scanning electron microscopy (SEM), and penicillin was selected as the target degradation pollutant to evaluate the photocatalytic degradation performance of the composites.
【Result】 The results show that after the fly ash cenospheres are treated with 2 mol/L nitric acid, there are many loose small holes and protrusions, and the TiO₂ nanoparticles could be evenly dispersed, which could effectively promote the separation of photo-generated electrons and holes, thus increasing its photocatalytic effect. The degradation rate of the composite photocatalyst with a loading amount of 19.1%, 25.4%, 34.57%, 44.47% and 54.61% increase with the increase of time, and the degradation rate of the photocatalyst with a loading amount of 44.47% is the highest, reaching 77%. When the loading amount is further increase to 54.61%, the degradation efficiency of the nano-TiO₂ composite photocatalyst exhibits a decreasing trend as the reaction time prolongs. Under the condition where the pH value is controlled at 8, the maximum degradation rate of the target pollutant can reach 79%. Meanwhile, the two different light sources employed in the experiment exert only negligible impacts on the overall photocatalytic degradation performance of the prepared composite material.
【Conclusion】 All tested inorganic anions can promote the photocatalytic reaction, and carbonate ions (CO₃^2-) exhibit the most significant promotion effect on the photocatalytic degradation process.

【Objective】 With the rapid expansion of high-end manufacturing sectors including new energy vehicles and wind power equipment, stricter standards are imposed on the high-temperature stability, coercivity and other key properties of permanent magnets. SmFe12-based magnets stand out as a next-generation candidate to replace conventional Nd-Fe-B magnets due to their low rare-earth dosage, high Curie temperature and superior high-temperature magnetic performance. Nevertheless, their large-scale industrialization is hindered by the intrinsic drawbacks of thermodynamically unstable 1∶12 main phase and inadequate coercivity. This work aims to systematically summarize the research progress on coercivity enhancement of SmFe12-based magnets and provide theoretical references for developing high-performance bulk SmFe12 permanent magnets.
【Method】 This paper adopts a literature review method. It elaborates two magnetic hardening mechanisms of nucleation and domain wall pinning during magnetization reversal, comprehensively sorts out prevailing modification technologies from three core perspectives: elemental doping, microstructure regulation and grain boundary diffusion.
【Result】 Elemental doping stabilizes the 1∶12 main phase yet weakens magnetization intensity. Dopants such as Zr, Co, V and Ti significantly improve coercivity, and the maximum coercivity of quinary SmFe12-based alloys reaches 1.26 T. Eliminating crystal defects and precisely tuning single-domain grain size are critical to boosting coercivity via the nucleation mechanism. Single-domain grains reduce local demagnetizing fields, and jet-milled powder achieves an optimal coercivity of 1.4 T, whereas mechanical pulverization introduces twin defects and accelerates reverse domain nucleation. Constructing non-magnetic grain boundaries through grain boundary diffusion represents the most promising coercivity-improving strategy at present. This technology forms core-shell isolation microstructures and raises coercivity up to 1.32 T, yet it is only applicable to thin films for the time being.
【Conclusion】 Future research should focus on enhancing phase stability, eliminating crystal defects and realizing large-scale grain boundary diffusion treatment for bulk magnets. Relevant technological breakthroughs will accelerate the industrialization of low-heavy-rare-earth SmFe12 permanent magnets and ease the supply shortage of Pr and Nd rare-earth resources.

【Objective】 Titanium matrix composites (TMCs) have attracted significant interest for lightweight, high-performance applications. Designing heterostructures has emerged as a key strategy to overcome the traditional strength-ductility trade-off in these materials. This review aims to consolidate recent progress in heterostructured TMCs, focusing on their fabrication routes, microstructural characteristics, mechanical properties, and the underlying mechanisms that enable their superior performance.
【Method and result】 This review summarizes recent progress in the fabrication, microstructural characteristics, mechanical properties, and underlying mechanisms of heterostructured TMCs. Firstly, the prevalent processing routes for achieving heterogeneous architectures are outlined. Subsequently, the microstructural features and resultant mechanical performances of TMCs are discussed, classified into distinct heterostructure types: network, layered, three-dimensional (3D), core-shell, and bimodal structures. The analysis indicates that these unique architectures effectively generate back-stress hardening that is fundamental to their superior strength and toughness.
【Conclusion】 Heterostructure design proves to be an effective strategy for overcoming the strength-ductility dilemma in TMCs. Future research should prioritize: (1) developing TMCs for high-temperature performance exceeding 800 ℃; (2) mitigating mechanical property anisotropy through microstructural control; (3) utilizing additive manufacturing to achieve novel reinforcement distributions; (4) advancing cost-effective, scalable production while evaluating additional service properties. This review provides a foundation for guiding the next generation of TMC development.

【Objective】 This study aimed to systematically review the application of electron backscatter diffraction (EBSD) in the microstructural characterization of high-entropy cemented carbides (HECCs). The objective was to clarify how EBSD was used to investigate grain structure, crystallographic orientation, grain boundary characteristics, phase evolution, and service-related degradation behavior. In addition, the study sought to identify the advantages and current limitations of EBSD when applied to complex multi-phase and multi-component systems such as HECCs, and to provide guidance for future research and methodological optimization.
【Method】 A comprehensive analysis of recent literature was conducted, focusing on EBSD-based investigations of HECCs. The study examined EBSD both as a standalone technique and in combination with complementary methods such as X-ray diffraction (XRD), transmission electron microscopy (TEM), and energy dispersive spectroscopy (EDS). Key analytical approaches included inverse pole figure (IPF) mapping for crystallographic orientation, grain size statistics, grain boundary misorientation distribution, and phase identification. Particular attention was given to studies involving sintering processes, heat treatment, and service conditions such as high temperature, corrosion, and wear.
【Result】 The results show that EBSD provides critical insights into the microstructure-property relationships of HECCs. Grain refinement and homogeneous distribution are shown to enhance hardness and fracture toughness through grain boundary strengthening mechanisms. A higher proportion of high-angle grain boundaries is found to effectively hinder crack propagation and improve mechanical reliability. EBSD analysis also reveals that high-entropy alloy binders suppress abnormal grain growth due to sluggish diffusion effects, leading to more stable microstructures. Furthermore, when combined with XRD, EBSD enables the identification of phase transformations, such as FCC-to-HCP transitions in multi-principal element binders, which are associated with increased hardness. The technique also demonstrates strong capability in correlating grain boundary characteristics with corrosion behavior, indicating that fine grains and special grain boundaries (e.g., Σ-CSL boundaries) contribute to enhanced corrosion resistance. In addition, EBSD effectively captures microstructural evolution during sintering and service, providing quantitative support for process optimization.
【Conclusion】 EBSD is demonstrated to be a powerful and indispensable tool for the characterization of HECC microstructures. It enables detailed analysis of grain orientation, grain boundary engineering, and phase evolution, thereby supporting the optimization of mechanical and functional properties. However, limitations remain in spatial resolution for nanoscale grains, sensitivity to sample preparation quality, and phase discrimination in complex multi-phase systems. Future developments should focus on integrating EBSD with advanced characterization techniques, improving data processing through machine learning, enhancing detector resolution, and establishing comprehensive material databases. These advancements will significantly improve the accuracy and efficiency of EBSD analysis and further promote its application in the design and development of high-performance HECC materials.

【Objective】 Additive manufacturing (AM) of aluminum alloys has emerged as a critical manufacturing solution for lightweight components in aerospace, new energy vehicles and advanced equipment sectors, owing to its exceptional design freedom and near-net-shape forming capability. However, conventional aluminum alloy systems face inherent bottlenecks in AM processes, including high hot cracking susceptibility, significant mechanical anisotropy, low tensile strength and poor corrosion resistance, which severely limit their engineering applications. This study aims to systematically clarify the modification mechanisms of typical alloying elements in AM-processed aluminum alloys, providing theoretical guidance for the development of high-performance aluminum alloy systems suitable for AM.
【Method】 This paper systematically reviews recent research progress on alloying-modified AM aluminum alloys, focusing on ten representative elements: Sc, Zr, Mn, Cu, Ti, Ce, Er, Mg, Li and Hf. The modification effects of each element are analyzed from multiple perspectives, including molten pool solidification behavior regulation, microstructure evolution, phase precipitation characteristics and strengthening mechanisms, combined with experimental data from published literature on mechanical property changes under different element addition amounts and heat treatment processes. Comparative analysis is conducted on the modification efficiency, cost performance and application limitations of different elements.
【Result】 The results demonstrate that alloying modification can effectively address the core pain points of AM aluminum alloys through four main mechanisms: (1) Sc, Zr, Er and Hf elements form L1₂-structured intermetallic compounds such as Al₃(Sc,Zr) as heterogeneous nucleation cores, which can refine grains by more than 60% and completely eliminate hot cracking; (2) Mn, Cu and Mg elements mainly exert solid solution strengthening effects, with 5.2 wt.% Mn addition increasing the ultimate tensile strength of AM aluminum alloys to 637 MPa; (3) Ce and Ti elements promote the formation of equiaxed grain structures, reducing mechanical anisotropy by over 40%; (4) Reasonable heat treatment processes can further promote the precipitation of nano-scale reinforcing phases, achieving a synergistic improvement of strength and plasticity. Among them, Sc/Zr composite modification shows the most comprehensive performance improvement effect, while Mg and Li elements have unique advantages in preparing ultra-lightweight AM aluminum alloys.
【Conclusion】 Alloying modification is a highly feasible technical path to optimize the comprehensive performance of AM aluminum alloys. Multi-element synergistic modification, which combines grain refinement, solid solution strengthening and precipitation strengthening effects, is the key development direction for future high-performance AM aluminum alloy design. Future research should focus on developing low-cost, high-efficiency alloying systems to replace expensive rare earth elements, and exploring lightweight alloy systems based on Mg and Li elements to meet the application requirements of extreme working conditions. The findings of this study provide important reference for the composition design, process optimization and engineering application of AM aluminum alloys.

【Objective】 High-entropy alloys (HEAs) have shown great potential in aerospace, energy, marine engineering, and other severe service environments owing to their high strength, good thermal stability, and excellent corrosion and wear resistance. However, conventional fabrication methods often suffer from element segregation, coarse microstructures, limited forming capability, and difficulties in producing complex components. Laser additive manufacturing (LAM), with rapid solidification and near-net-shape forming capability, provides a promising route for the preparation and performance regulation of HEAs. This review summarizes recent progress in LAM of HEAs and discusses its effects on microstructure, properties, defect control, and future development.
【Method】 The basic characteristics and classification of HEAs are first introduced. Then, the main LAM technologies, including selective laser melting and directed energy deposition, are reviewed in terms of forming features, process advantages, and application characteristics. The influence of rapid solidification, non-equilibrium microstructure formation, and element redistribution on phase constitution, grain morphology, and performance evolution is analyzed. In addition, post-processing methods such as heat treatment, thermomechanical treatment, and surface strengthening are discussed for defect optimization and property improvement.
【Result】 Studies show that LAM can effectively refine grains, promote the formation of metastable phases and non-equilibrium microstructures, and improve the strength, hardness, wear resistance, corrosion resistance, and high-temperature stability of HEAs. Selective laser melting is suitable for high-precision complex components, while directed energy deposition is more advantageous for large-scale forming, repair, and compositional regulation. Nevertheless, defects such as pores, cracks, residual stress, element segregation, and phase instability may still occur due to complex melt-pool behavior and thermal cycling. Appropriate post-processing can reduce these defects and further improve comprehensive performance.
【Conclusion】 LAM provides an effective technical pathway for the fabrication and application of high-performance HEAs. Future research should focus on the coordinated optimization of alloy composition and process parameters, clarification of the process-microstructure-property relationship, and integration of simulation, in-situ monitoring, and intelligent manufacturing. These efforts will promote the controllable preparation and engineering application of laser additively manufactured HEAs.

【Objective】 This paper explores the factors affecting the carbon content of tantalum powder in the reduction process of potassium fluotantalate.
【Method】 Factors affecting the carbon mass fraction of tantalum powder from two aspects of raw materials and process are analyzed, such as different sodium injection amounts after the sodium end point, different of metal sodium, the entry of air into the reaction system, different pH dilution salts, and different circulation methods.
【Result】 It was found that when the excess weight of metal sodium is below 1-3 kg, the mass fraction of C in tantalum powder does not change much, when the excess weight of metal sodium increases significantly in the mass fraction of 3-6 kg and with the increase of the excess proportion of metal sodium,the mass fraction of C shows an upward trend. The C mass fraction of tantalum powder produced using metal sodium that has entered the air is higher than than produced using metal sodium that has not entered the air. The air entered into the reaction system has little effect on the carbon mass fraction of the product. The pH of the dilution salts is below 6.5, and the C mass fraction does not fluctuate much. The pH of the dilution salts is above 6.5, the C mass fraction is slightly higher. The mass fraction of C flowing through a buffer tank with a thinner inlet is slightly higher than that flowing through a buffer tank with a thicker inlet.
【Conclusion】 The production process should ensure the purity of raw materials and reasonable process,as to ensure that the carbon content of tantalum powder produced is within the qualified range.