K439B nickel-based alloy is a novel high-temperature material capable of operating at 800 ℃， which has been widely used in critical components such as combustion chamber housings for aerospace engines. However， the traditional casting process struggles to meet the high qualification rate requirement for high-precision forming of thin-walled complex components. In this study， laser powder bed fusion （LPBF） technology is used to process samples. By adjusting the laser power （140-220 W） and scanning speed （600-1400 mm/s）， and using characterization techniques including optical microscopy， scanning electron microscopy， and electron backscatter diffraction， the effects of process parameters of LPBF on the relative density and microstructure are analyzed. The processing window （laser power：160-220 W， scanning speed：1000-1200 mm/s） for manufacturing K439B superalloy via LPBF is summarized， and two process parameters （160 W-1000 mm/s and 220 W-1200 mm/s） within the window are selected to process samples for tensile tests at room-temperature and 800 ℃. The results show that irregular pores and Ti-C carbides are prone to form under the 160 W-1000 mm/s （volume energy density（VED） = 66.67 J/mm³） parameter. In contrast， the samples processed under 220 W-1200 mm/s （VED = 114.58 J/mm³） have a uniform microstructure without carbide， whose ultimate tensile strength at room temperature is over 1 GPa and elongation is over 25%. However， at 800 ℃， all LPBF samples exhibit brittleness （with an elongation after fracture of approximately 0.5%）， which is mainly attributed to the lack of γ' phases and dissolution of cellular substructures inside the grains.This study provides process guidance and theoretical support for the engineering application of LPBF fabricated K439B alloy.

Titanium alloys are universally recognized as the prime option for core load-bearing structures in aero-engines， owing to their remarkable blend of high strength， low density， exceptional creep resistance， and outstanding corrosion resistance. The reliability of titanium alloy joints has a direct bearing on the operational safety and service life of aero-engines. Linear friction welding （LFW）， an efficient solid-state joining technique that is precisely tailored to the precision manufacturing requirements of aero-engines， offers substantial benefits such as near-net shaping， minimal welding flaws， and excellent joint integrity. It facilitates the high-quality and consistent bonding of titanium alloy components and plays a pivotal role in the fabrication and repair of complex， integrated components like blisks.This paper centers on the research and application demands of LFW technology for aero-engine components. It provides an in-depth review of the progress in titanium alloy LFW across four key areas： process experimentation， physical simulation， finite element numerical modeling， and post-weld heat treatment. It systematically summarizes the current research status and identifies the existing challenges in each field. Moreover， the paper points out future research directions， including the evaluation of long-term service performance， multi-scale numerical simulations ranging from the microstructural to the macroscopic level， and the optimization of modified LFW process parameters. These efforts are crucial for promoting the wider industrial application of titanium alloy LFW technology.

Fused filament fabrication （FFF） technology boasts significant advantages， including high design flexibility， mold-free operation， and the capacity to rapidly construct complex structures， making it a key method for 3D printing of continuous carbon fiber reinforced thermoplastic polymer （CCFRTP）. However， during the actual printing， CCFRTP often experiences a decline in mechanical properties due to insufficient interfacial bonding between the thermoplastic matrix and the continuous carbon fiber reinforcement， as well as a high internal porosity. To address this issue， this paper analyzes two major factors influencing the performance—the resin matrix and the carbon fiber reinforcement. Based on this， it reviews the recent advances in FFF technology， examines the effects of various printing parameters on mechanical properties， along with optimization strategies. Finally， future development directions and application prospects are discussed.

Additive manufacturing offers a transformative approach to fabricating ceramics for water treatment through precise multi-scale structural control. This paper comprehensively reviews the application advancements of stereolithography and extrusion-based additive manufacturing techniques for fabricating water treatment ceramics in oil-water separation， organic pollutant degradation， and seawater desalination scenarios. However， persistent challenges involve resolution limitations below 100 nm constraining precise separation layers， trade-offs between structural complexity and mechanical integrity causing delamination risks under pressure， and scalability barriers elevating costs. Future advancements will require self-healing smart ceramics enabling autonomous crack repair alongside machine learning-guided co-design strategies to optimize structure-function relationships. This review aims to provide a reference for the research on additive manufacturing of water treatment ceramics， to promote the industrial application of additive manufacturing technology in high-throughput and long-life water treatment ceramics.

Refractory high-entropy alloys （RHEAs）， owing to their exceptional high-temperature properties， show great potential for use in extreme environments such as aerospace systems. However， the inherent complexity of their multicomponent systems poses significant challenges to the efficiency of conventional alloy design methods. Although additive manufacturing （AM） overcomes some limitations of traditional fabrication routes， its intrinsic non-equilibrium solidification behavior and complex process-parameter space introduce new challenges in microstructural control and property optimization. In this context， machine learning （ML） offers a data-driven paradigm for uncovering the intricate composition-structure-property relationships in RHEAs and provides a powerful tool for intelligent materials design. This review systematically summarizes the latest advances in the application of ML to RHEAs， with particular focus on key issues in AM scenarios. On the one hand， the roles of ML in phase prediction， strength and ductility optimization， and hardness design are discussed. On the other hand， ML-enabled strategies for process-parameter optimization， defect mitigation， and microstructural tailoring in AM are thoroughly analyzed. Despite notable progress， several challenges remain， including the scarcity of AM-specific datasets， the limited generalization capability of process-property models， and the insufficient integration of physical mechanisms. Therefore， establishing standardized databases oriented toward additive manufacturing， developing machine learning models integrated with physical constraints， and constructing an integrated process-microstructure-property optimization framework are key directions for promoting the transition of refractory high-entropy alloys in the field of additive manufacturing from “printable” to “designable”.

This study delves into the impact of positive and negative defocusing distances on the surface quality， densification， and mechanical properties of 316L stainless steel specimens fabricated through laser powder bed fusion （LPBF）. The results show that specimens form with positive defocus outperformed those formed with negative defocus， a phenomenon attributes to the enhanced stability of the molten pool under positive defocus conditions. When the defocusing distance reaches ±3 mm （surpassing the Rayleigh length）， it leads to a sharp decline in laser power density and a substantial deterioration in spot penetration capability. Under these circumstances， incomplete melting of the metallic powder occurs， which undermines the interlayer metallurgical bonding and triggers a proliferation of defects within the specimens， ultimately resulting in a degradation of their mechanical properties. As the defocusing distance increases from -3 mm to 3 mm， the laser power density initially roses and then declines. The laser power density attains at a defocusing distance of +0.5 mm， reaching 61.33 kW/mm². At this optimal condition， the part exhibits superior performance： the upper surface hardness is 200.1HV₅， the lateral surface hardness is 206.2HV₅， the tensile strength is （647 ± 27） MPa， the yield strength is （525 ± 30） MPa， and the elongation reaches （49.4 ± 3.1）%. An optimal power density input facilitates effective regulation of the molten pool morphology， achieving a dual-process optimization： ensuring adequate melting of the powder while simultaneously suppressing defect generation.

Laser welding is performed on 3 mm thick dissimilar 6063/A356 aluminum alloys， and the welded joints are subjected to two different post-weld heat treatments： direct aging （DA） and solution aging （T6）. The microstructure and mechanical properties of the welded joints are analyzed using optical microscopy， scanning electron microscopy， and transmission electron microscopy， combined with microhardness testing and tensile testing. The results indicate that under appropriate welding parameters， the weld exhibits excellent formation， and the tensile strength of the as-welded joint reaches 192.5 MPa， which is 73.7% of that of the 6063-T6 base metal. After DA treatment， the tensile strength of the welded joint increases to 233.8 MPa， representing a 21.5% enhancement compared to the as-welded joint. Transmission electron microscopy analysis further reveals that after DA treatment， a large number of acicular β" phases precipitate in the heat-affected zone on the 6063 aluminum alloy side. These nano-sized precipitates exhibit a good coherent or semi-coherent relationship with the Al matrix， effectively hindering dislocation slip and significantly enhancing the joint strength. After T6 treatment， the Si-rich eutectic network in the weld seam is fragmented and spheroidized， transforming into a spherical or polygonal morphology. Consequently， although the tensile strength of the joint decreases， its elongation is significantly improved compared to that of the as-welded and DA-treated joints.

Carbon fiber reinforced thermoplastic composites （CFRTP） show great application potential in aerospace and other fields owing to their advantages of light weight， high specific strength， rapid prototyping， and weldability. As a commonly used lightweight metal in the aerospace industry， titanium alloy is a material that can be directly bonded to CFRTP without corrosion defects. Achieving high-performance joining between the two is of great significance for reducing structural weight， cutting carbon emissions， and ensuring the operational safety of equipment. However， due to the differences in their physical and chemical properties， joining the two materials poses numerous challenges. This paper reviews the research progress on the welding of CFRTP and titanium alloy. It summarizes and analyses the process characteristics of various welding technologies， surface treatment methods of titanium alloys， and interface joining mechanisms. Furthermore， it looks forward to the common issues that need to be addressed in the welding of CFRTP and titanium alloys， aiming to provide a reference for the large-scale assembly application of CFRTP/titanium alloy hybrid structure.

Additive manufacturing of nickel-based superalloys holds significant promise for applications in aero-engines and gas turbines. Evaluating the mechanical properties of these materials is crucial for facilitating their use in load-bearing components. This study investigates the high-cycle fatigue performance of the GH3536 alloy， which is fabricated via laser powder bed fusion and then undergoes solution heat treatment， with the assessment carried out at room temperature.By utilizing X-CT technology and performing fracture analysis， the defect characteristics of the material are comprehensively characterized. Furthermore， a quantitative analysis is conducted to explore the relationship between defect size and fatigue limit. The results reveal that the alloy contains porosity and lack-of-fusion defects， with surface and subsurface defects being the main contributors to fatigue fracture. The defect density in vertical samples is lower， leading to a slightly higher fatigue limit compared to that of horizontal samples.By using the effective defect size in the fracture source region of the fatigue sample， a more accurate and conservative prediction of the fatigue limit can be made. This is achieved by enhancing the Kitagawa-Takahashi （K-T） diagram with the El-Haddad model. The fatigue life of the alloy can be predicted by integrating this approach with the fatigue life characterization method based on the ratio proposed by Murakami， in combination with the El-Haddad model. This combined method provides higher prediction accuracy， especially for vertical samples with low defect density.

Based on the in-situ fatigue test technique of scanning electron microscope （SEM），the small crack behavior of selective laser melting （SLM） TC4 alloy is studied. The focused ion beam （FIB） technique is used to manufacture the simulative initial defects in the process of additive manufacturing，and the initiation and propagation behavior of small cracks induced by defects are observed under cyclic loading. The results show that under cyclic loading，small cracks are easy to initiate at the surface defect，and the crack fatigue initiation life is short. The fatigue life of SLM TC4 alloys is mainly consumed in the small crack propagation stage. Affected by the microstructure，the small cracks are more likely to propagate along the α/β interface. Due to the random orientation of α laths，the path of small cracks is deflected several times in the initial propagation stage，exhibiting a mixed mode of propagation along α lamellae and through α lamellae within grains， resulting in significant scatter in crack growth rates. At the stable crack propagation stage，the plastic slips of the crack tip are obvious，the influence of microstructure is reduced，and the propagation path tends to straighten. Comparative analysis with long crack growth data indicates that SLM TC4 alloy exhibits a significant “small crack effect”.

To improve the high-temperature performance of GH5188 cobalt-based superalloy， 10%（volume fraction） TiC particle-reinforced GH5188 composites are fabricated by laser melting deposition （LMD）. The microstructure and tensile properties are investigated， and the interfacial forming mechanism and the cause of the high-temperature performance degradation are discussed. The results show that the composite consists of TiC， （W，Ti）C_{1 -x}， and the austenitic γ phase. The submicron-thick （W，Ti）C_{1 -x} interfacial layer forms between the TiC particles and the matrix. The interfacial layer originates from the partial dissolution of TiC and the diffusion and substitution of W elements during the laser melting deposition process. At room temperature， the ultimate tensile strength （UTS） of the composite reaches 1198.9 MPa， which is 24.3% higher than that of the matrix alloy （964.3 MPa）. However， at 1000 ℃， the UTS of the composite is 128.7 MPa， which is lower than the 162.5 MPa of the matrix alloy， with a decrease of 20.8%. The degradation in high-temperature strength is mainly due to the consumption of W elements in the matrix by the （W，Ti）C_{1 -x} interfacial layer， resulting in decrease in its mass fraction and weakening the solid-solution strengthening and dislocation-pinning effects on the matrix.

The 316L/Q370qE stainless steel clad plates with a thickness of （3+32） mm are studied by using X-groove welding process. The effects of welding current on the microstructure and properties of the welded joints of clad plate are analyzed by means of optical microscopy， scanning electron microscopy， transmission electron microscopy， energy dispersive spectroscopy. The results show that the weld metal microstructure of the stainless steel cladding layer and transition layer is austenite and skeletal δ ferrite. The microstructure of carbon steel weld metal is proeutectoid ferrite， acicular ferrite， and ferrite side-plate. And a fine-grained bainite is formed in the area adjacent to the stainless steel transition layer. As the welding current increases， the content of δ ferrite in the weld metal of stainless steel decreases and its shape becomes more irregular. The microstructure in the local weld metal of the carbon steel coarsens. There is extensive mutual diffusion of elements in the interface between the weld metal of transition layer and carbon steel. At the same time， the microstructure in the heat-affected zone of the stainless steel and carbon steel coarsens. However， the change in the original layered interface of the clad plate is not obvious. The tensile fractures of the welded joints of clad plate with different currents all occur in the heat-affected zone. When the current is 230 A， the tensile properties are the best， and the tensile strength and elongation reach 557 MPa and 23.9%， respectively. The low-temperature impact absorption energy of both the carbon steel weld metal and fusion zone near the stainless steel cladding layer is about 20 J lower than that at the position keeping away from the stainless steel cladding layer. The impact energy difference in the heat-affected zone at the two positions is more significant. The change of welding current in the range of 210-280 A has little influence on the intergranular corrosion performance of stainless steel cladding layer. Therefore， when using 230 A and 30-31 V parameters to weld the stainless steel transition layer and cladding layer， the impact performance difference of the weld metal of carbon steel on both sides of the X-groove is the smallest， and the tensile properties of the welded joint of clad plate are the best.

The rotorcraft structures have typical characteristics such as small batches， multi-specifications， complex shape and high-performance requirements. Additive manufacturing technologies have the ability to integrally form complex shapes and structures and produce on demand， which can achieve lightweight and rapid preparation of structures. It is an ideal process preparation solution for rotorcraft structures. However， although additive manufacturing technologies originating from rapid prototype preparation have been used in rotorcraft structures for more than 10 years， due to many challenges such as the stability of additive manufacturing technology structural parts preparation， extremely high R&D certification costs and rapid technology iteration， for rotorcraft structures， additive manufacturing technology still belongs to the category of new materials， new processes and new technologies. In order to meet the efficient application demand of additive manufacturing technology in domestic rotorcraft structures， based on the application status and development trend of additive manufacturing technology in foreign rotorcraft structures are reviewed and examined， development suggestions for the engineering application of additive manufacturing technology in domestic rotorcraft structures are proposed： constructing quantitative evaluation criteria for the application of additive technology in rotorcraft structures， establishing structural design optimization technology for additive manufacturing， developing high-performance materials， new additive manufacturing processes and high-quality post-processing methods for additively manufactured structural parts， realizing real-time monitoring and process parameter control of additive manufacturing process and universal and efficient airworthiness.

To delve into the impacts of multiple brazing thermal cycles at varying peak temperatures on the microstructure and properties of GH4169 alloy， this study conducted a comprehensive examination of how brazing thermal cycle processes influence the precipitates， grain size， tensile properties， and stress-rupture properties of the alloy.The findings reveal that as the thermal cycle temperature rises， the quantity of δ-phase precipitation diminishes， and its morphology undergoes a transformation from needle-like to rod-like and eventually to granular. Within the temperature range of 970-1010 ℃， the grain size experiences minimal alteration. However， when the temperature surpasses 1020 ℃， significant grain growth occurs. Both tensile strength and hardness initially ascend and then descend with an increase in the thermal cycle temperature， reaching their peak values at 1010 ℃. This phenomenon is mainly attributed to the dissolution of an appropriate amount of δ phase and the complete precipitation of γ″ and γ′ strengthening phases at this temperature， while the grain size does not show significant coarsening.The room-temperature impact toughness demonstrates distinct trends across different thermal cycle ranges. In the 970-990 ℃ range， it decreases with rising temperature due to the partial transformation of the δ-phase morphology from needle-like to rod-like. In the 990-1010 ℃ range， it increases with temperature as the δ phase dissolves and the strengthening-phase-free zone vanishes. Nevertheless， a further increase in the thermal cycle temperature leads to a reduction in toughness because of grain growth.The stress-rupture life initially declines and then rises with an increase in the thermal cycle temperature， hitting its lowest point in the 990-1000 ℃ range. This is caused by the partial transformation of the δ-phase morphology from needle-like to rod-like， which promotes microvoid nucleation and reduces the alloy's creep resistance. When the temperature further rises above 1020 ℃， the extensive precipitation of γ″ strengthening phases， along with significant grain growth， substantially enhances the alloy's creep performance. However， the substantial decrease in the needle-like δ-phase content results in increased notch sensitivity.Taking into account both mechanical properties and notch sensitivity， it is recommended to employ brazing thermal cycles around 1010 ℃ to achieve a well-balanced combination of strength and stress-rupture performance. For service environments with higher notch sensitivity requirements， a thermal cycle temperature in the range of 970-980 ℃ can be selected to minimize the risks of creep failure.

To tackle the issue of microstructural segregation in nickel-based alloy weldments and the consequent degradation of joint mechanical properties， this study delves into the impacts of two post-weld heat treatment schedules on the microstructural features and mechanical behavior of gas tungsten arc-welded Incoloy 825 nickel-based alloy joints.The results reveal that both heat treatment procedures lead to a notable coarsening of fine grain boundary carbides in the base metal （BM）. Moreover， the γ′ phase can be precipitated within BM grains through solution treatment combined with two-stage aging. Both post-weld heat treatments facilitate extensive precipitation of the δ and Laves phases in the WZ interdendritic zones， effectively alleviating segregation. Nevertheless， joints subjected to solution treatment and two-stage aging develop microcracks at the interface between the unmixed zone （UMZ） and the heat-affected zone （HAZ）， along with the formation of micropores within the HAZ. Mechanical characterization indicates a substantial increase in microhardness in the weld zone （WZ） after both heat treatment protocols. Solution treatment with single-stage aging maintains hardness levels in the HAZ and BM that are comparable to those in the as-welded state. Joints treated with solution treatment and single-stage aging show a marginal reduction in tensile strength， accompanied by a 9.2% improvement in uniform elongation， and fracture exclusively occurs within the BM. Conversely， the tensile strength of joints treated with solution treatment and two-stage aging significantly rises to 795 MPa， an increase of 17.3%， while the uniform elongation decreases. The fracture localization shifts to the UMZ/HAZ interfacial regions and adjacent HAZ areas， presenting a ductile-brittle mixed fracture morphology.

AA5052 aluminum alloy and 304 stainless steel with the thickness of 3 mm are welded with ZnAl22 flux-cored wire by tungsten inert gas （TIG） fusion-brazed welding. The effect of different welding currents and wire feeding speeds on the macro morphology of butt joints，microstructure of weld seam/steel interface，tensile properties and fracture behavior of the joints is studied. The results show that when the welding current is 110 A and the wire feeding speed is 24 mm/s，the maximum average tensile strength of the butt joints reaches 166 MPa. Fracture primarily occurs at the weld seam/steel interface， exhibiting typical brittle fracture characteristics. The weld seam/steel interface is composed of η-Fe₂Al₅Zn_0.4，η-Zn（Al） and α-Al. With the increase of the welding current，the tensile strength of the joint first increases and then decreases. The white granular δ-FeZn₁₀ appears in the η-Fe₂Al₅Zn_0.4 interfacial layer，and Zn elements are segregated at the η-Fe₂Al₅Zn_0.4/steel interface. The Zn-rich phases at the η-Fe₂Al₅Zn_0.4/steel interface are determined to be Γ-Fe₃Zn₁₀ by transmission electron microscopy. It is found that excessively high welding current leads to cracking at the η-Fe₂Al₅Zn_0.4/steel interface. With the increase of wire feeding speeds，the thickness of η-Fe₂Al₅Zn_0.4 decreases gradually，and the phase composition at the weld seam/steel interface remains unchanged. Based on thermodynamic analysis，it is concluded that the formation sequence of intermetallic compounds （IMCs） at the weld seam/steel interface is η-Fe₂Al₅Zn_0.4，δ-FeZn₁₀，Γ-Fe₃Zn₁₀.

Performance metal powder serves as a crucial material in 3D printing additive manufacturing， as the properties of the powder directly influence the microstructure and overall performance of 3D-printed components. The plasma rotating electrode process （PREP） employs high-temperature plasma to melt the end face of a rapidly rotating electrode rod. Subsequently， the molten liquid film is fragmented into droplets， which then solidify into powder under the action of centrifugal force. This paper provides a comprehensive review of the development history， equipment types， powder preparation principles， and performance characteristics of the PREP process. It also delves into the impact of process parameters on the powder's properties and discusses the application of numerical simulation methods in understanding the powder formation mechanism and controlling powder particle size. Furthermore， the paper reviews the progress made in applying PREP-prepared powder materials in the 3D printing manufacturing of aerospace， medical equipment， nuclear power， rail transit， and other equipment sectors. Finally， it is highlighted that the PREP milling process is poised to evolve towards higher purity， finer particle size， narrower particle size distribution， fewer inclusions， higher sphericity， greater efficiency， and lower costs.

Superalloy hollow turbine blades are key components of aero engines， and the ceramic core used for forming the complex cooling channel structure inside the blade is a key transitional component in the blade preparation. The stereolithographic additive manufacturing process for ceramic cores has the advantages of no need for molds， high precision， and short process cycle， providing a reliable new process for the high-precision preparation of complex-structured ceramic cores. Among them， defect control in the additive manufacturing process of cores has become the key to the preparation of high-precision ceramic cores. This work summarizes the current research status of printing， degreasing and sintering defect control at home and abroad. The defect regulation mechanism is summarized， and the research status of defect regulation is reviewed from aspects such as slurry preparation， printing and degreasing-sintering process optimization， and the addition of mineralizers. On this basis， it is proposed that curing behavior， pore distribution law and deep learning are important development directions for future research on ceramic cores.

Ceramic materials， with their high strength， high hardness， excellent high-temperature resistance， and superior corrosion resistance， have broad application prospects in fields such as machinery， electronics， aerospace， and biomedical engineering. However， traditional ceramic processing techniques are restricted by mold dependency and limited design freedom， making it difficult to meet the demand for efficient and rapid manufacturing of complex components. Laser additive manufacturing （LAM）， including laser powder bed fusion （LPBF） and laser directed energy deposition （LDED）， primarily achieves three-dimensional solid formation through layer-by-layer laser melting and stacking， providing a revolutionary solution for the rapid， customized manufacturing of complex-shaped ceramic components. However， the crack defects generated during the rapid solidification process in LAM severely constrain performance enhancement and engineering applications， becoming an urgent challenge and research hotspot in this field. This paper outlines the forming principles and the latest domestic and international progress of ceramic materials using LPBF and LDED technologies. It focuses on discussing the crack formation mechanisms， microstructural evolution， mechanical properties， and their influencing factors in direct laser additive manufacturing of ceramics. Additionally， it systematically summarizes strategies for suppressing cracks， such as forming preheating， process optimization， ultrasonic assistance， and microstructural control， along with their effects. Finally， it provides an outlook on the future development trends and core challenges of ceramic LAM technology， focusing on directions such as multi-physical field coupling simulations， material composition optimization， and multi-field assisted technologies， offering guidance for promoting the rapid development of ceramic laser additive manufacturing technology.

Aiming at the problem that the internal short carbon fiber （C_sf） of carbon fiber reinforced silicon carbide （C_sf/SiC） composites prepared by laser powder bed molten/liquid silicon permeation （LPBF/LSI） is prone to be eroded by molten Si， which limits the strengthening and toughening effect of fibers on the matrix and restricts the performance improvement of C_sf/SiC composites formed by LPBF/LSI. This study propose to coat pyrolytic carbon （PyC） and silicon carbide （SiC） coatings respectively on the surface of C_sf by hydrothermal carbonization and dip coating-pyrolysis processes， and C_sf/SiC composites are prepared through LPBF/LSI. The influence of the fiber surface coating on the microstructure and mechanical properties of C_sf/SiC composites is studied. The results show that the SiC coating can prevent the direct contact between Csf and molten Si， avoid the dissolution-precipitation reaction at the interface between the two， and thereby protect C_sf. Compared with the C_sf/SiC composites with C_sf and C_sf@PyC， the internal fibers of the C_sf/SiC composites with C_sf@SiC still retained better original structure， while the C_sf inside the former two showed reactive erosion. The fibers retained due to SiC coating protection improved the flexural strength and fracture toughness of C_sf/SiC composites to a certain extent through crack deflection， coating de-bonding and fiber pulling mechanisms， which are 7.1% and 8.3% higher than those of C_sf/SiC composites with C_sf and C_sf@PyC， respectively. The maximum reaches 246.09 MPa and 3.28 MPa·m^1/2. In this study， the synergistic improvement of the strength and toughness of C_sf/SiC composites is achieved through the optimization of fiber surface coatings， providing a certain theoretical basis for the preparation of high-performance C_sf/SiC composites by LPBF/LSI.

Stereolithography 3D printing technology achieves high-precision fabrication of ceramic cores with complex structures by selectively curing a paste composed of photosensitive resin and ceramic powder using ultraviolet laser. However， the ceramic paste experiences light scattering during curing， leading to an expansion of the cured area， which adversely affects printing accuracy and part performance. Based on a high-solid-loading， thixotropic silica ceramic paste system， the mechanism of ultraviolet absorbers in the preparation of light-curing 3D-printed ceramic core samples and its effect on the properties of the ceramic cores are systematically investigated. By experimentally optimizing the type and amount of ultraviolet absorber， its effects on the printing accuracy， microstructure， sintering shrinkage， and mechanical properties of the ceramic core samples are explored. The results show that an appropriate amount of ultraviolet absorber regulates the spatial distribution of light， effectively reduces scattering of light， and thereby improves the printability of the paste while enhancing interlayer bonding， microstructural uniformity， and mechanical properties. However， there exists an optimal threshold for the amount of ultraviolet absorber. Excessive addition leads to excessive attenuation of light intensity， prolongs the single-layer exposure time， and reduces printing efficiency. Through systematic experimental optimization， 0.25% （mass fraction） TINUVIN B75 is determined as the optimal type and concentration of absorber， achieving the best balance between printing accuracy and efficiency.

The ceramic slurry is prepared using alumina and calcium carbonate powder as matrix materials，polyvinyl alcohol solution as a binder，and acetic acid as a dispersant. Different porous alumina-based ceramics are printed by micro-extrusion 3D printing technology. The effects of hole structure and thickness on the sewage filtration performance and its affecting mechanism of porous alumina-based ceramics are investigated. The results show that the multi-layer cross-hole alumina-based ceramic samples with the hole diameter less than 0.1 mm are successfully fabricated by the micro-extrusion 3D printing method with a stepwise 30° filling angle and varying filling rates. The cross hole distribution can divert sewage flow and increase the effective filtration area，while the thicker multi-layer cross-hole porous alumina-based ceramic provides a longer path for sewage filtration，facilitating the removal of small molecular particles in the sewage. When the filling rate is 90% and the ceramic thickness exceeds 8 mm，the sewage turbidity removal rate exceeds 90%，and the filtered sewage turbidity is below 10 NUT，satisfying the industrial and agricultural requirements for water. Based on adsorption，screening-filter cake-deep bed filtration mechanism，a filtration mechanism model of the multi-layer cross-hole and through-hole structures is established. The multi-layer cross-hole alumina-based ceramics with submicron and micron-sized holes perform better in terms of permeability and filtration ability，compared to through-hole alumina filtration ceramics，possessing higher potential for sewage treatment applications. This research provides valuable reference for the application of micro-extrusion 3D printing technology in the field of porous ceramic filtration.

Ti6Al4V alloy is fabricated firstly by selective laser melting （SLM） and then followed by hot stamping treatment. The corrosion resistance and wear resistance of SLM Ti6Al4V alloy before and after hot stamping treatment are comparatively studied using electrochemical corrosion and friction wear tests， and the underlying mechanisms of the performance differences are elucidated. The results indicate that in simulated body fluid， the hot-stamped SLM-formed Ti6Al4V specimens exhibit reduced corrosion resistance， with an increase in corrosion current density and a decrease in passive film thickness from 3.19 nm to 1.21 nm. The primary reason is that hot stamping causes grain coarsening in the SLM-formed Ti6Al4V specimens， with grain size increasing from 1.37 μm to 1.51 μm， and the proportion of low-angle grain boundaries rising by 1.41%， thereby accelerating the corrosion rate and degrading corrosion resistance. Additionally， the volumetric wear loss of the hot-stamped specimens increases from 0.314 mm³ to 0.474 mm³， indicating a decline in wear resistance， with the wear mechanism dominated by the combined effects of abrasive wear and oxidative wear.

The control of WC grain size homogeneity in cemented carbide produced by binder jetting additive manufacturing （BJAM） is crucial for optimizing its mechanical properties；however， related studies remain limited. This research investigates the effect of vanadium carbide （VC） addition on the microstructure and mechanical properties of WC-12Co cemented carbide to prevent abnormal WC grain growth. The results demonstrate that the addition of VC significantly improves the surface roughness of WC-12Co cemented carbides. Specifically， the addition of 0.5%（mass fraction， the same below） VC and 1.0%VC reduces the surface roughness by 21.49% and 17.77%， respectively. Compared to the plain WC-12Co carbide without VC， the average WC grain size in the cemented carbides with 0.5%VC and 1.0%VC decreases from 1.83 μm to 1.57 μm and 1.61 μm， respectively. VC effectively inhibits abnormal WC grain growth and promotes a more uniform distribution of WC grain sizes. Furthermore， the addition of 0.5%VC increases the Vickers hardness by 3.3% and the bending strength by around 3%. Additionally， VC incorporation significantly reduces the friction coefficient and the wear rate of the BJAMed carbides， enhancing their wear resistance. These findings suggest that VC addition offers a promising strategy for improving the performance of cemented carbides in additive manufacturing， providing a valuable technical route for further development in this field.

Zirconia （ZrO₂） is widely used in dental restorations for its excellent mechanical properties， continuously improved optical properties， and durability. CNC machining for zirconia dental restorations is mature yet inflexible， with a phase transformation risk that can affect performance and stability. Additive manufacturing， with its high degree of freedom and accuracy， can create complex 3D geometries unachievable by subtractive manufacturing， while reducing material waste， energy consumption， and production time. These features have drawn increasing attention to additive manufacturing in the dental restoration market. Zirconia-based restorations， a significant part of the dental market， have achieved performance in additive manufacturing comparable to that of traditionally manufactured （CAD/CAM） restorations. Therefore， it is necessary to summarize the latest achievements of zirconia in dental restoration manufacturing. This article summarizes the various applicable additive manufacturing methods （including vat photopolymerization， material extrusion， material jetting， powder bed fusion， and binder jetting） for zirconia-based dental restorations based on the latest research， provides the available dental materials， manufacturing examples， and performance requirements， and identifies the challenges for current additive manufacturing of dental restoratives. This review aims to help dentists and researchers better understand the current zirconia additive manufacturing technology and choose suitable dental materials and methods when manufacturing restorations or prostheses.

Ceramic additive manufacturing technology， through high-precision structural design and multi-material integrated molding， provides a new approach for the field of catalysis， ranging from carrier customization to precise regulation of active sites. Catalyst carriers prepared based on ceramic additive manufacturing technology feature higher mass transfer efficiency， freely formed geometric shapes， and excellent thermal stability， demonstrating significant potential in reducing production costs and advancing green energy initiatives. This review systematically examines four principal additive manufacturing technologies applied to ceramic catalyst carriers： direct ink writing， stereolithography， digital light processing， and fused deposition modeling. The review summarizes four major kinds of ceramics applied as catalyst carriers， and outlines the current research landscape of additive manufacturing in fabricating diverse ceramic catalyst carriers， with a focused analysis on their applications in automotive exhaust purification， denitrification processes， chemical synthesis， solid oxide fuel cells， and solar thermochemical cycle reactions. Finally， the key challenges and future development directions of additively manufactured ceramic catalyst supports are discussed. Future research should focus on the development of novel multifunctional ceramic material systems， the synergistic design of high-precision and multiscale architectures， the coupled regulation of active sites and mass transfer behavior， as well as green， low-energy fabrication and post-processing strategies， to promote the large-scale application of additively manufactured ceramic catalyst supports in energy conversion and environmental catalysis.

PA12 material has good thermal stability and radiation resistance， and has broad application prospects in deep space manufacturing. However， PA12 materials prepared by fused deposition modeling （FDM） on the ground generally have structural defects such as high porosity and poor interlayer bonding， which limit their mechanical properties and make it difficult to directly use them in deep space environments. To address this issue， this study proposes the modification of printing materials using extreme environmental conditions in deep space to improve their mechanical properties and meet the high requirements for structural integrity and mechanical performance in deep space manufacturing. By simulating typical variables in deep space environments， including high-temperature heat treatment， ultraviolet irradiation， and anaerobic solidification， the effects of different processes on the microstructure and mechanical properties of PA12 materials are systematically evaluated. The results show that after 10 min of heat treatment at 200 ℃， the bending strength of the sample increases by 66.2%； after introducing 3% （mass fraction， the same below） photoinitiator and 4% photocrosslinking agent and irradiating with UV for 2 min， the tensile strength of the sample increases by 17.5%； after doping with 3% anaerobic adhesive and irradiating for 2 min， the compressive strength of the sample increases by 34.4%. Finally， multiple processing techniques are combined to synergistically regulate the sample， resulting in a 75%，94.2%， and 62.2% increase in tensile， bending， and compressive strength， respectively. This study explores the impact of simulating extreme deep space environments on the properties of PA12 materials， verifying the feasibility of in-situ modification of PA12 materials using deep space environmental variables. This provides an effective technical path and theoretical support for the in-orbit manufacturing of high-performance elastic components in deep space environments.

Continuous fiber reinforced metal matrix composites，as representatives of high-performance structure-function integrated materials，the innovation of their preparation technology and the expansion of engineering applications have always been core issues in the field of materials. This paper mainly reviews the forming process of continuous fiber-reinforced metal matrix composites，systematically combing the advantages，disadvantages，and applicability of traditional forming technologies for fiber metal matrix composites. Aiming at the bottlenecks of traditional processes，high-quality integrated forming methods for new composites such as 3D printing technology and fiber metal prepreg preparation technology are discussed. The feasibility and application trends of these methods in forming structural parts of fiber-reinforced metal matrix composites are also discussed，with the aim of providing a reference for the development direction of high-quality preparation processes for metal matrix composites and their engineering applications.

Synchrotron radiation technology serves as a “super microscope” for unveiling multi-scale physical metallurgy behaviors during additive manufacturing （AM）， providing groundbreaking research tools to decode the “black box” challenges inherent in AM processes. This paper review systematically summarizes recent advances in synchrotron radiation applications for AM：in imaging， ultrafast X-ray imaging with high spatiotemporal resolution enables in situ observation of melt pool dynamics， defect formation mechanisms， and solidification behavior， revealing key phenomena such as keyhole fluctuation-induced porosity and Marangoni force-driven defect suppression； in diffraction， ultrafast X-ray diffraction quantitatively resolves phase transformation kinetics and residual stress evolution during rapid solidification. Furthermore， this work explores emerging trends in integrating synchrotron technology with deep learning and multiphysics simulations， while envisioning its potential for AM process optimization， intelligent defect detection， and novel material development. It is pointed out that such technology establishes a theoretical foundation and technical pathway for transitioning AM from empirical trial-and-error to mechanism-driven methodologies.

Aiming at the interface defect issue of 45/CuSn5 alloy cladding layer，this study proposes a method for suppressing interface defects and optimizing the performance of 45/316L/CuSn5 gradient cladding layer prepared by laser cladding additively using 316L as a transition layer. By systematically comparing the microstructure and element distribution of the interface between the 45/CuSn5 single cladding layer and the 45/316L/CuSn5 gradient cladding layer，the control mechanism of the 316L transition layer is revealed，and the properties of the substrate and gradient cladding layer are compared and studied. The results show that the gradient cladding layer forms a defect-free metallurgical bonding interface due to the introduction of 316L transition layer，and the interface exhibits obvious elemental interdiffusion. The high concentration gradient of Cr element effectively reduces the interface energy and suppresses crack initiation. The diffusion of Cu element into 316L promotes the formation of a Cu-Ni solid solution，while the transition from 316L to the CuSn5 surface cladding layer realizes a transition from austenite （γ-Fe） to an α-Cu solid solution. This crystallographic structure transition effectively suppresses the formation of interfacial brittle phases， thereby achieving interface defect suppression. In the friction and wear test under dry friction conditions with a load of 20 N and reciprocating linear motion for 30 min，the average friction coefficient of the gradient cladding layer is 0.1486，significantly lower than that of the substrate（0.4080）；the wear rate is 1.723 mm³·N^-1·m^-1，which is 30.21% lower than that of the substrate（2.469 mm³·N^-1·m^-1），achieving optimized wear resistance of the substrate. Electrochemical corrosion tests further show that in a 3.5%NaCl solution，the corrosion current density of the gradient cladding layer（3.105×10^-6 A·cm^-2）is one order of magnitude lower than that of the substrate（4.839×10^-5 A·cm^-2）， with the corrosion rate reduced by 93.58%， demonstrating significantly enhanced corrosion resistance.

The study focuses on the nickel-based superalloy ZGH451 manufactured by additive manufacturing， conducting heat treatment experiments with different processes. By analyzing the microstructure and mechanical properties， an optimized heat treatment regime suitable for this alloy has been developed， which consists of short-time high-temperature solution treatment followed by two-stage aging. The results indicate that the optimal heat treatment process is as follows： 1250 ℃ for 15 min （air cooling） + 1100 ℃ for 4 h （air cooling） + 850 ℃ for 24 h （air cooling）. After complete heat treatment， the element segregation within the alloy is eliminated， resulting in a γ' phase microstructure with favorable size （436 nm）， area fraction （63.74%）， and cubic morphology. Additionally， the tensile properties at 760 ℃ are significantly improved， with a tensile strength of 1142 MPa and an elongation of 22.8%.

To overcome the drawback of the brittle borides formed in the stainless steel joint brazed using Ni-based filler metals and further improve the mechanical properties of the joint， a small amount of Cu powders are added into the BNi-2 filler metal to suppress the formation of brittle borides in the joints. The 304 stainless steels are brazed using the BNi-2 and BNi-2 with Cu as filler metals， respectively. The influences of holding time， brazing temperature， and Cu content on the microstructure and mechanical properties of the brazed joints are investigated. The results indicate that for the BNi-2 filler metal， increasing the brazing temperature and time are favorable for reducing the boride content formed in the joint center. In addition， increasing the brazing temperature and time can accelerate the intergranular diffusion of borides， thereby leading to a degradation of joint shear strength. For the BNi-2 filler metal with Cu， when the Cu content is 1%（mass fraction，the same below）， the borides in the joint center are inhibited remarkably， forming a full Ni-based solid solution in the joint center. The joint shear strength obtained is （713.9±16.4） MPa， which is 19% higher than that of the joint without Cu additive. The joint failure occurs at the base metal/filler metal interface， recognized as a ductile fracture. However， when the Cu content increases to 5%， the borides reprecipitate in the joint center， resulting in the reduction of shear strength. In this case， the joint failure evolves to a composite mode with the co-existence of ductile and brittle fracture.

This study addresses the issue of magnetic property degradation during the welding of 1J85 permalloy. Comparative experiments are conducted on 1.5 mm thick annular 1J85 permalloy using two processes： plasma arc welding （PAW） and plasma arc heat treatment welding （PAHTW）， to systematically investigate the effects of these processes on the microstructure and magnetic properties of welded joints. The microstructure， elemental distribution， magnetic permeability and coercivity of the joints are analyzed using optical microscopy， scanning electron microscopy， energy-dispersive spectroscopy， and soft magnetic property testing. The results show that under the PAW process， the morphology of the weld joint exhibits a funnel-shaped structure with a wider top and narrower bottom； under the PAHTW process， multi-layered regional boundaries are formed in the weld zone， with significant grain growth， reduced number of cellular subcrystals， and decreased grain boundary density. Energy-dispersive spectroscopy analysis indicates that the content of the non-magnetic element Si in the weld zone relatively reduces by approximately 50% compared with that in the PAW process. Compared with the PAW process， after PAHTW treatment， the initial magnetic permeability of the joint increases from 40.12 mH/m to 78.81 mH/m， the maximum magnetic permeability increases from 72.63 mH/m to 113.41 mH/m， and the coercivity decreases from 1.70 A/m to 1.24 A/m.

Nickel-based superalloys are widely used in high-temperature turbine components of aviation engines， and inertia friction welding （IFW） is widely used for the connection of nickel-based superalloy disc and shaft due to its solid-phase bonding property and high weld quality. With the emergence of new materials and structures， there are greater challenges for inertia friction welding. Therefore， this paper mainly reviews the current research status of the formation mechanism of weld seam， microstructural evolution characteristics， mechanical properties， and numerical simulation of welding process in inertia friction welding joint of nickel-based superalloy. At the same time， the formation mechanism of continuous drive friction welding joint of nickel-based superalloy is summarized for comparison. Finally， the key issues such as how to smoothly extrude flash， the selection of heat treatment process and the deterioration of corrosion resistance of joints after heat treatment are put forward in the relevant research in the future.

As a typical refractory metal material， tungsten alloy possesses high hardness， excellent wear resistance， and good radiation shielding ability， making it widely applicable in various industrial fields. However， its poor formability hinders the manufacturing of complex structural components using traditional preparation methods such as liquid phase sintering. Additive manufacturing technology， which fabricates three-dimensional structural parts by layer-wise accumulation of forming planes， has unique advantages in producing complex components. Consequently， it has attracted extensive attention in the field of tungsten alloy component manufacturing. The development and application of additive manufacturing technology in the preparation of tungsten alloys in recent years are systematically introduced， and the influencing factors of tungsten alloy toughening during the forming process are further discussed. Firstly， the current research status of various tungsten alloy additive manufacturing technologies both domestically and internationally is presented， and their applicable scenarios are summarized. Then， the toughening approaches for tungsten alloys during forming， including second-phase particles and alloying treatments， are comprehensively reviewed. Finally， the development direction of additive manufacturing of tungsten alloys in the fields of composition optimization， process parameter control， post-processing， multi-material printing and intelligent manufacturing integration to improve the mechanical properties of formed alloys and expand the application fields is summarized and prospected.

Cold spraying technology has a number of unique characteristics， most notably the solid-state metal powder deposition. This property confers the technology with significant technical advantages and application potentials in the domains of coating preparation， high-efficiency and high-speed repair， and additive manufacturing. Nevertheless， when applying for high-strength nickel-based superalloy materials， this technology remains confronted with significant technical challenges， including high coating porosity， inadequate strength， and an absence of plasticity. In this paper， the critical deposition conditions and influencing factors of cold-sprayed superalloys are systematically reviewed， focusing on the microstructure characteristics of deposited materials and their correlations with properties （especially tensile properties）， and summarizing the main methods of microstructure and performance optimization， such as post-spray heat treatment， post-spray hot isostatic pressing， laser-assisted cold spraying， and in-situ shot peening-assisted cold spray deposition. In the future， for expanding the engineering applications of cold-sprayed high-temperature alloys， it is necessary to modify the particle deformation conditions and expand the deposition window， to develop the hybrid treatment methods to improve the coating property， as well as lowering the process costs. These measures will provide a theoretical basis and technical guidance for its applications in the fields of aerospace.

Additive friction stir deposition （AFSD） is a technology with several advantages for aerospace manufacturing. It is particularly valuable because it can deposit materials at low temperatures while retaining high quality and efficiency. This article introduces the operations of AFSD in detail and investigates its effect on three types of precipitation-reinforced aluminum alloys. Key challenges hindering the production of high-strength aluminum alloy components through AFSD are highlighted. AFSD utilizes solid-phase deposition to avoid problems like porosity and thermal cracking that can occur with other types of deposition， such as laser and arc depositions. However， the slow cooling of the deposited metal and the long residence time in the sensitive temperature range can cause issues. Subsequent layers exert a thermal effect on the previous layers during the AFSD process. This can lead to coarsening of the precipitates in the middle and lower regions， resulting in decreased strength in these areas. The top layer remains unaffected， but has poorer mechanical properties compared to the base material. To improve performance， aging treatment can be used to cause reprecipitation of some elements dissolved during AFSD， but it does not reach the values achieved by solid solution and aging （T6） treatment. T6 treatment after AFSD can renew uniformly distributed fine-strengthening precipitates， but it triggers abnormal grain growth （AGG） in the deposited material. Therefore， it is generally not recommended to subject solution treatment to metals deposited with AFSD. Further research should focus on alloy design， composite reinforcement and innovative techniques， which are essential to obtain high-strength precipitation-reinforced aluminum alloy components through AFSD.

The improved process combining a polybenzimidazole （PBI） polymer nozzle with axial center powder feeding is employed to study the nozzle clogging behavior and its impact on coating deposition. Multi-scale characterization of the coating morphology and microstructure is carried out using X-ray computed tomography（X-CT）， optical microscopy， and electron backscatter diffraction. The results show that in the existing process， aluminum powder softening causes adhesion to the inner wall of the SiC nozzle， forming clogging materials. This leads to a powder agglomeration on the coating surface and a porosity of 0.32%. In contrast， the PBI nozzle， when used with the axial center feeding process， significantly reduces particle adhesion and forms a uniform gas-solid two-phase flow， enabling continuous and stable deposition. The resulting coating exhibits significant internal particle plastic deformation with the porosity reduced to 0.16%. Based on the optimized process， aluminum metal additive manufacturing experiments are carried out， achieving continuous spraying for 2 h without nozzle clogging and depositing a 38 mm thick coating on an aluminum alloy substrate. X-CT analysis indicates that there are no significant defects at the interface or within the deposit. The in-plane and out-of-plane tensile strengths of the deposit are about 180 MPa and 80 MPa， respectively， indicating significant anisotropy.

To promote the further application of high-strength aluminum alloys in the aviation field，the 7050-T7451 aluminum alloy with 4 mm thickness is carried out by laser-melt inert-gas（MIG）hybrid welding. The results show that a well-formed weld seam can be obtained with reasonable matching of welding parameters，while welding at higher speeds is easy to produce cracks. When the welding speed is controlled at 0.9 m/min or below，and the weld back-width ratio is controlled above 0.4，the cracks and porosity defects can be effectively suppressed. The weld zone is mainly composed of equiaxed grain structures with significant differences in size. Near the fusion zone，there is a fine-grained layer approximately 20-50 μm wide，and only a minimal amount of columnar grains forms adjacent to this fine-grained layer. No phase transformation or recrystallization occurs in the heat-affected zone. The as-welded joint achieves an average tensile strength of approximately 377 MPa， equivalent to about 73% of the base metal strength， significantly outperforming the tensile properties of laser self-fusion welded joints.

In the aerospace field， welding serves as the primary joining process for TA3 alloy components，and the microstructure and mechanical properties of its welded joints have a significant impact on the service safety of welded components. This study compares the tensile properties of the base metal and welded specimens and studies the deformation morphology before and after tension using scanning electron microscopy combined with electron backscatter diffraction. The results show that the microstructure of TA3 alloy is equiaxed α grains before welding， and massive， acicular and serrated α grains appear after welding. The yield strength （378 MPa） and tensile strength （458 MPa） of welded specimens are higher than that of base material specimens， but the elongation is lower. The reason is that after the base meterial sample is welded， the welding temperature has the effect of aging treatment on the sample. There exists aging hardening， and the grain size inside the weld area becomes smaller， which will increase the tensile strength. Because the microhardness of the weld zone is obviously higher than that of the base metal zone， the fracture of the welded joint is located in the base meterial zone. The deformation mechanism of the weld zone is stress-induced deformation twin （ \mathrm{2} \overline{\mathrm{1}} \overline{\mathrm{1}}2）［ \mathrm{2} \overline{\mathrm{1}} \overline{\mathrm{1}}3］ and （ \overline{\mathrm{2}} \mathrm{1}12）［ \overline{\mathrm{2}} \mathrm{1}13］， with a Schmid factor of 0.038， exhibiting high shear stress and strong coordination of grain deformation. Deformation twins （ \overline{\mathrm{2}} \mathrm{11}2）［ \mathrm{2} \overline{\mathrm{1}} \overline{\mathrm{1}}3］ also appear in the base material region， but the Schmid factor is 0.078， indicating a relatively high degree of stress concentration.