Additive manufacturing is a near-net shaping technology that builds three-dimensional solid parts by depositing material layer by layer. It offers unique advantages in producing metal parts with complex structures. As a result, it has been widely used in key fields such as aerospace, biomedical and high-end mold manufacturing. However, the unique forming process of additive manufacturing introduces defect characteristics that differ from those in traditional manufacturing methods. These issues severely affect the service reliability of the formed parts and have become a critical challenge for the technology. This paper systematically summarizes the research findings of AECC Additive Manufacturing Technology Innovation Center on defects in additively manufactured metal materials. It focuses on the morphological features, formation mechanisms and effects on mechanical properties of typical defects such as holes, lack of fusion, inclusions and cracks. The paper also analyzes the role of hot isostatic pressing in closing defects and improving mechanical properties. To address current research gaps, it suggests further studies in several areas. These include revealing the relationship between defect formation mechanisms and process parameters, developing metal materials specifically for additive manufacturing, establishing defect acceptance standards based on part service requirements, and advancing intelligent online monitoring and closed-loop control technologies. These efforts aim to promote further progress of additive manufacturing.

Brazing technology is one of the indispensable key joining technologies in the manufacturing of aerospace structures, and it is widely applied to the joining of components operating under high-temperature, high-stress, and complex service conditions. This paper systematically reviews the research progress and application status of key brazing technologies for aerospace structures, with a focus on the brazing research developments of complex components such as aero-engine turbine blades, aircraft metal honeycomb sealing structures, and heat exchangers. Meanwhile, for advanced aerospace structural materials including ceramic matrix composites, TiAl high-temperature alloys, and Nb-Si refractory alloys, this paper comprehensively analyzes their current weldability research status and major technical bottlenecks in the brazing process. Finally, it is pointed out that the integration of numerical simulation and machine learning technologies, combined with multi-principal alloy design and micro-alloying regulation strategies, can significantly improve the efficiency of composition screening and process optimization for high-performance specialized brazing materials. This approach will accelerate the establishment of a comprehensive technical standard system covering the entire temperature range and manufacturing process, and further advance the theoretical research on dissimilar material joining, thereby providing robust technical support for advanced aerospace manufacturing.

As an emerging moulding technology, 3D printing has steadily matured and is poised to supplant the traditional hot-press injection moulding technology, emerging as a pivotal approach for manufacturing ceramic cores in aerospace turbine blades. Nevertheless, 3D-printed ceramic cores produced through 3D printing display significant anisotropy in mechanical properties, including sintering shrinkage rate and strength, owing to their layered structure and directionally arranged porosity. This anisotropic characteristic severely impedes their manufacturing potential and application scope, posing a critical challenge that demands urgent resolution. This paper offers a systematic summary of the manifestations of anisotropy in 3D-printed ceramic cores, clarifies the underlying formation mechanisms, formulates evaluation criteria, and puts forward effective control strategies. Additionally, it delineates future research directions, encompassing material system innovation, process optimization, comprehensive property regulation, multi-technology integration, and intelligent manufacturing methods. These endeavors lay a solid theoretical groundwork for promoting the high-performance realization and large-scale application of 3D-printed ceramic cores.

During the welding thermal cycle, changes in the distribution and morphology of precipitates within the heat-affected zone (HAZ) often lead to typical softening, making HAZ the weakest region of the welded joints. In this study, a novel welding strategy is proposed by integrating fiber laser welding with thermally stable Ce-containing rare earth precipitates. This approach enables the tailored regulation of precipitate structures in both the fusion zone and HAZ, simultaneously refining precipitate distribution, narrowing the HAZ width and mitigating softening, thereby enhancing the overall mechanical performance of the joint. The results reveal the formation of numerous micron- and submicron-sized precipitates within the fusion zone, which are dispersed along dendritic arm boundaries. These particles serve to effectively pin dislocations and hinder their movement during deformation, contributing to fusion zone strengthening. Meanwhile, the thermally stable rare earth precipitates in the HAZ help preserve the original precipitate structure of the alloy, maintaining the HAZ width at around 100 μm after thermal cycling and substantially reducing microstructural degradation caused by welding. Tensile testing confirms that, with Ce micro alloying and optimized laser welding parameters, the resulting joints exhibit excellent mechanical properties, achieving a lap shear strength of 74.4% relative to the base metal. These findings validate the feasibility and effectiveness of the proposed welding strategy for high-quality joining of rare earth magnesium alloys.

The integrated structure of monolithic catalysts not only reduces flow resistance and enhances mass and heat transfer efficiency, but also overcomes the inherent limitations of granular catalysts, thereby endowing them with more efficient and stable catalytic performance. They have been extensively employed in fields such as space stations, manned spacecraft and satellite attitude and orbit control. However, conventional molding techniques fail to achieve customized production of complex macroscale structures and flexible regulation of microscale pore structures during catalyst preparation, and the backwardness of preparation processes has hindered the further development of monolithic catalysts. Currently, scholars at home and abroad have begun to adopt additive manufacturing technology for the design and fabrication of monolithic catalysts, among which the design and selection of catalyst 3D structure, molding method and carrier material according to application requirements are the key research focuses. This paper firstly outlines the application limitations of traditional molding methods for monolithic catalysts and highlights the technical advantages of additive manufacturing techniques. Subsequently, it elaborates on the design and regulation methods of catalyst structures, analyzes the structural characteristics and post-processing methods of carriers under different molding approaches, and summarizes common printing materials and carrier properties. Finally, based on the practical application status of 3D-printed monolithic catalysts in aerospace and other industries, this paper systematically prospects the future development trends of catalyst additive manufacturing, as well as the core challenges, including the protection of catalyst pore structures, maintenance of specific surface area and loading of active components during high-temperature molding.

Ceramic cores are key transfer components for single crystal superalloy hollow turbine blades in aeroengines. To address the insufficient impact resistance of the fine structures in ceramic cores, this work innovatively adopts photocuring additive manufacturing to develop a composite-formed alumina-silica based ceramic core. Dense α-Al₂O₃ phase ceramic fine structural components are produced, with dimensional accuracy and three-point bending strength reaching ±0.003 mm and 314 MPa, respectively, exhibiting excellent impact resistance. The main body of the ceramic core, which encapsulates the alumina-based ceramic components via hot injection molding, has a bending strength of 12 MPa and an apparent porosity of 29.5%, ensuring favorable collapsibility and leachability. The relationship between the separation gap width of the heterogeneous alumina-silica material interface and the thermal expansion coefficient, shrinkage rate, and elastic modulus of two materials is established. Micro-texture design on the surface of additively manufactured alumina-based ceramic components is adopted to form an interlocking alumina-silica interface microstructure on the composite-formed ceramic core, which improves the physical bonding strength of the heterogeneous interface and effectively compensates for interfacial separation during thermal processes. Basic casting verification of single-crystal hollow turbine blades is achieved using the composite-formed alumina-silica based ceramic core, with high dimensional conformity of process holes and no excess metal in the inner cavity. It demonstrates broad application prospects in the precision casting of superalloy blades for aeroengines.

To improve the high-temperature performance of brazed repair joints for service cracks in K465 superalloy blades, a novel Co-Cr-Ni-W-Al-Ti-Ta-B brazing filler metal is employed to braze K465 superalloy with gap widths of 0.05 mm and 0.2 mm under the condition of 1220 ℃/15 min. The microstructure, elemental distribution, and high-temperature tensile properties of two joints are analyzed. The results show that the brazing filler metal exhibits excellent metallurgical compatibility with the base metal, with significant interdiffusion of elements occurring during the brazing process. The joint with a 0.05 mm gap consists of a γ/γ′ dual phase matrix with dispersed γ′ phase, as well as compound phases including (W, Cr)B, Ti-rich boride, and NiAl. For the joint with a 0.2 mm gap, the introduction of superalloy powder as a filler material results in dispersed and refined compound phases, while the phase types remain unchanged. The high-temperature tensile properties at 1000 ℃ of two joints are comparable: the tensile strength of the 0.05 mm and 0.2 mm gap joint is 383 MPa and 396 MPa, respectively, reaching approximately 70% of the K465 base metal. Due to the favorable metallurgical compatibility between the brazing filler metal and the base metal, as well as the strengthening effect of the B2-ordered NiAl phase, two kinds of brazed joints exhibit excellent high-temperature tensile properties.

High-temperature resistant ceramic matrix composites (HT-CMCs) have demonstrated immense application potential in aerospace, energy, and other extreme service environments, thanks to their outstanding attributes such as exceptional high-temperature resistance, high strength, low density, and excellent chemical stability. Traditional manufacturing processes are constrained in fabricating HT-CMCs with complex shapes and high performance. In contrast, additive manufacturing (AM) technology has paved a new way for the production of HT-CMCs with intricate structures, leveraging its unique capability of layer-by-layer construction. This technology substantially improves the functional properties and structural efficiency of materials by enabling the direct fabrication of complex internal features, like cooling channels. It also supports performance-oriented precise control and customized production according to specific service requirements, while significantly reducing material waste and effectively cutting down manufacturing costs. This paper focuses on the additive manufacturing technology of HT-CMCs. It introduces the technical principles and current application status of this technology, and places particular emphasis on expounding the latest research advancements both domestically and internationally in material system design, forming technologies, and process optimization for additively manufactured HT-CMCs. Furthermore, this paper sets out the future trends of additive manufacturing for HT-CMCs. In terms of material-process synergy, the focus is on overcoming the bottleneck of interface bonding in multi-material printing and developing composite processes to achieve multi-functional integration and gradient structures. Regarding the construction of intelligent systems, the aim is to establish a “digital control-real-time monitoring-parameter optimization” system and reduce trial-and-error costs through AI-based parameter adjustment. In the realm of modularization and circular manufacturing, the emphasis is on developing interchangeable standardized modules and innovating ceramic waste recycling technologies to enhance material utilization rates. All these endeavors are aimed at promoting its engineering application in cutting-edge fields.

The rapid progress in aerospace engineering places an urgent demand for advanced structural materials that exhibit outstanding mechanical properties under ultra-high temperature operating conditions. While recently developed refractory high-entropy alloys (RHEAs) hold promising application prospects, they are still confronted with challenges, including room-temperature brittleness and elemental segregation, which present significant hurdles in manufacturing processes. Additive manufacturing (AM) technology offers distinct advantages in fabricating RHEAs, such as suppressing elemental segregation, refining microstructures, and enabling the production of components with complex geometries, thereby revealing the substantial research potential. This paper firstly introduces the main technical methods for AM-fabricated RHEAs. Subsequently, it systematically summarizes their microstructural features, elemental distribution patterns, and phase composition characteristics, along with an overview of their mechanical performance at both room and elevated temperatures. To address critical process challenges, such as cracking and porosity in AM-produced RHEAs, we not only review recent research achievements but also propose innovative strategies that combine composition optimization and grain boundary engineering to enhance the AM process. Finally, this paper makes prospects for further enhancing the room-temperature plasticity and high-temperature strength by introducing grain boundary strengthening elements or high-entropy ceramic strengthening phases through additive manufacturing technology in the future, as well as for the preparation of large-sized RHEAs complex components by suppressing cracking and residual stress.

TiAl alloys exhibit poor room-temperature ductility, which poses a challenge for traditional casting and forging processes to fulfill the manufacturing demands for complex structural components. Selective laser melting (SLM) technology, renowned for its short manufacturing cycle, high material utilization, and exceptional forming accuracy, is deemed well-suited for fabricating complex parts in the aerospace industry. In this research, Ti48Al2Cr2Nb alloy powder is mixed with 4% (mass fraction) FeMo60 alloy powder to formulate an alloy with a nominal composition of Ti47Al3.5Cr1Nb1Mo1Fe. By employing a chessboard overlap scanning strategy (which mitigates thermal stress during processing) and optimizing printing parameters, SLM fabrication of the TiAl alloy with a remarkably low defect rate (only 0.49%) is successfully accomplished. Moreover, the samples are characterized using X-ray diffraction and scanning electron microscopy to explore the underlying reasons for microstructure formation. Additionally, a substantial portion of the α₂ phase in the as-printed alloy is converted into the γ phase through heat treatment. Simultaneously, the unmelted FeMo60 powder from the printing process is dissolved, achieving solid solution strengthening. This phenomenon leads to a significant 30% enhancement in the compressive strength. This study offers a crucial reference for the preparation of high-performance TiAl alloys with complex geometries.

Wire-arc additive manufacturing (WAMM) is an emerging manufacturing technology that employs metal wire as the raw material and arc as the heat source. It offers advantages in fabricating large and complex parts. Nevertheless, it still faces challenges, including prolonged fabrication cycles, intricate path planning, and substantial residual stress. In this study, we explore the optimization of the manufacturing path for wire-arc additive manufacturing when fabricating complex structural components, aiming to mitigate the significant residual stress and strain induced by suboptimal manufacturing paths. Finite element software is utilized to optimize the manufacturing path, and a unit body of a grid component with excellent forming quality has been successfully produced using the optimized path. Through finite element analysis, it can be revealed that for the unoptimized path, the equivalent residual stress at the thin-wall after cooling reaches 361 MPa, while that at the nodes after cooling is 666 MPa. In contrast, for the optimized path, the equivalent residual stress at the thin-wall after cooling is 206 MPa, and the equivalent residual stresses at two nodes after cooling are 260 MPa and 427 MPa, respectively. Compared to the unoptimized path, the optimized path leads to a 61% reduction in residual stress at the nodes and a 43% decrease in stress at the thin-wall. Moreover, the difference in residual stress between the nodes and the thin-wall is smaller than that of the unoptimized path, resulting in less deformation and fewer defects caused by residual stress. The grid component unit body fabricated using the optimized path exhibits well-combined melt tracks and superior forming quality, with no discernible residual stress deformation. This effectively validates the feasibility of the optimized path in controlling residual stress during the wire-arc additive manufacturing of grid components.

The TiAl4822 (Ti-48Al-2Cr-2Nb) alloy, renowned for its exceptional high-temperature mechanical properties and low density, stands out as a highly promising candidate for critical aerospace components. However, its high chemical reactivity and inherent room-temperature brittleness pose significant challenges to the conventional manufacturing of large and complex geometries. Laser directed energy deposition (LDED), characterized by its high fabrication efficiency and remarkable process flexibility, has emerged as a crucial approach for preparing TiAl4822 alloy components. Nevertheless, the rapid melting-solidification cycle during LDED induces a substantial temperature gradient and residual stress, which results in component cracking. Currently, there is no well-established method to completely prevent crack formation. In this study, a dense and crack-free thin-walled TiAl4822 alloy component with dimensions of 30 mm×25 mm×6 mm is successfully fabricated using the whole high-temperature-assisted LDED technique. An investigation is conducted on their macro-morphology, microstructure, porosity, and microhardness. The results reveal that the thin-walled TiAl4822 alloy specimen prepared by LDED at room temperature is prone to brittle fracture primarily through cleavage, and its microstructure mainly comprises fine equiaxed grains. After implementing whole high-temperature assistance at an integral temperature of 800 ℃, the grains in the deposited layer transform from bottom to top into inclined columnar grains. The porosity is significantly reduced from 0.05% to 0.008%, accompanied by a more uniform pore-size distribution, and no macroscopic cracks are observed on the surface. Concurrently, the microhardness decreases from 390.46HV_0.2 to 354.94HV_0.2, which can be attributed to grain coarsening, a decrease in grain-boundary density, and precipitate evolution under high-temperature conditions. Overall, the integral high-temperature-assisted LDED effectively inhibits crack initiation and the formation of large pores while homogenizing the microstructure, providing a novel pathway for high-density, high-performance TiAl4822 preparing.

This study systematically investigates the effects of long-line and short-line scanning strategies on the microstructure and mechanical properties of GH5188 superalloy fabricated by laser powder bed fusion (LPBF). Metallography and SEM results reveal that both strategies produce mixed microstructures composed of columnar and equiaxed grains. Due to the shallower melt pool and insufficient remelting, the short-line strategy retains finer grains at the melt-pool center, leading to further grain refinement (17.17 μm). In contrast, the long-line strategy provides a more stable heat-flow direction, resulting in stronger〈001〉texture development along the build direction and a slightly larger average grain size (20.86 μm). Mechanical testing shows that the two strategies lead to similar tensile strength and ductility at room temperature. At 980 ℃, the tensile strengths are comparable, while the elongation of the long-line specimens is 28.6% higher than that of the short-line specimens. Under the 927 ℃/90 MPa stress rupture condition, the long-line specimens exhibit a significantly longer rupture life (50.2 h±1.8 h) and higher ductility (10.1%±0.5%) than the short-line specimens (45.3 h±2.1 h; 7.6%±0.4%). Cross-sectional analysis shows that the short-line specimens contain more densely distributed cracks, along with pronounced carbide precipitation and coarsening at grain boundaries, indicating higher grain-boundary damage sensitivity. Fractographic analysis further confirms that cracks preferentially propagate along grain boundaries. These findings clarify the microstructural origins of high-temperature performance differences and provide guidance for optimizing LPBF scanning strategies for GH5188 alloy.

The K418B superalloy is fabricated utilizing laser powder bed fusion (LPBF) technology, and an analysis is conducted to examine the impact of process parameters on microdefect, density, microstructure, and hardness by OM, SEM and hardness tester. This is achieved by varying the laser power (ranging from 140 W to 220 W) and scanning speed(between 600 mm/s and 1400 mm/s). The findings reveal that both laser power and scanning speed significantly influence the relative density and defect distribution of the samples. Specifically, low energy density leads to the formation of irregular pores, whereas high energy density is associated with the emergence of spherical pores and solidification cracks. Excessive or insufficient volume energy density (VED) results in decreased density and impaired performance. The optimal processing conditions are identified as a laser power of 180 W and a scanning speed of 1400 mm/s, under which the sample density exceeds 99.95%, with minimal surface defects and only a small quantity of solidification cracks. Microstructure reveals distinct melt pool boundaries and cellular structure, accompanied by a Vickers hardness of 366.8 HV_0.2. Notably, the grains at the melt pool boundaries are coarse, with cellular columnar crystals spanning multiple melt pools, indicating rapid solidification. The hardness initially increases and then decreases with VED, aligning with changes in pore content and density. The study attributes cracks primarily to thermal stress and provides a foundational basis for optimizing LPBF processing parameters of K418B alloy, holding potential engineering applications for enhancing the manufacturing quality of critical aero engine components.

IN718 alloy components are widely employed in high-temperature parts for aerospace applications. However, traditional machining methods are not only time-consuming but also lead to inefficient material utilization. This study introduces the fabrication of IN718 alloy through wire-laser directed energy deposition (W-LDED) technique. The alloy’s phase composition, microstructure, types of precipitated phases, and grain characteristics are characterized using X-ray diffraction, scanning electron microscopy, energy-dispersive spectroscopy, and electron backscatter diffraction. The mechanical properties of the alloy are evaluated using a universal tensile testing machine and a microhardness tester. The matrix of the IN718 alloy consists of the γ phase, with Laves precipitate phase located at the grain boundaries or sub-grain boundaries. Notable differences in surface microstructures and properties are observed across various planes. The XOY surface predominantly exhibits equiaxed grains with the smallest average grain size, whereas the XOZ and YOZ surfaces comprise a mix of equiaxed grains and coarse columnar grains, with the YOZ surface displaying the largest average grain size. The highest tensile strength, reaching 842.5 MPa, is recorded along the Y direction, accompanied by an elongation of 17.5%. Conversely, the highest elongation, at 29.5%, is noted in the X direction, with a tensile strength of 818.7 MPa. The hardness values of the XOY, XOZ, and YOZ surfaces are 314HV_0.2, 267HV_0.2, and 229HV_0.2, respectively.

Integration of polymer-derived SiOC(Fe) ceramic technology with 3D printing successfully enables the development of a photosensitive polymer precursor resin modified with vinyl-ferrocene (VcFe). This resin combines low viscosity, high photosensitivity, and excellent curing strength, enabling fabrication of precursor models with complex geometric structures and micro-nano features. Following pyrolysis at 1000 ℃ in an argon atmosphere, structurally intact and uniformly shrunken SiOC(Fe) ceramic components are obtained, with a mass retention rate of 45.27%, a density of 1.89 g/cm³, and a linear shrinkage of 32.94%. The study systematically investigates phase evolution and volumetric shrinkage behavior during pyrolysis and characterized the ceramic hardness (achieving 5.93 GPa after pyrolysis at 1000 ℃). This work effectively validates the feasibility of fabricating complex-structured SiOC(Fe) ceramics via 3D printing combined with polymer-derived ceramic technology, providing guidance for its practical application.

Additive manufacturing technology provides a novel approach for the production of complex-structured silicon nitride ceramics. In this study, the microstructural and strength evolution of additively manufactured silicon nitride after continuous thermal exposure for 24 hours in an oxygen-containing atmosphere at 1200-1500 ℃ are investigated. The morphology, phase compositions and element distribution are characterized by SEM, XRD, EBSD and EPMA. The results show that with increasing exposure temperature, α→β phase transformation occurs, and the volume fraction of β-Si₃N₄ increases from 63.02% to 74.15%. Meanwhile, the grain size of silicon nitride grows from 1.33 μm at 1200 ℃ to 1.97 μm at 1500 ℃. The flexural strength exhibits a rise-then-fall trend with increasing temperature, reaching a peak value of 722.67 MPa at 1200 ℃ and dropping to a minimum of 242.67 MPa at 1500 ℃, which represents a reduction of approximately 66.00% compared to the unexposed condition. Grain coarsening, as well as the formation of pores and microcracks during thermal exposure, are the primary causes of strength degradation. In addition, high-temperature oxidation reactions lead to the formation of mechanically weak SiO₂ phases and introduce dimensional inaccuracies, further compromising the mechanical performance of the additively manufactured silicon nitride. As a result, flexural strength continues to decrease with increasing exposure temperature. This study reveals the microstructural and mechanical evolution mechanisms of additively manufactured silicon nitride ceramics under extreme high-temperature service conditions, providing a theoretical foundation for improving their service reliability and process optimization.

The additive manufacturing process offers a solution for fabricating complex hollow structures that are challenging to realize through traditional ceramic preparation methods. However, defects are often inevitable during the additive manufacturing process. In this study, silicon carbide ceramics with complex hollow structures are prepared using the stereolithography (SLA) additive manufacturing process. Industrial computed tomography (CT) non-destructive testing techniques are employed to observe and analyze macroscopic defects, such as cracks. The initiation and propagation mechanisms of cracks are investigated, and the influence of structural features on crack propagation is explored. The results indicate that printing corners and holes in the component are weak regions prone to stress concentration, which can lead to crack formation or further cracking. Therefore, particular attention should be paid to the printing process and the removal of residual powder. Through process optimization such as structure optimization and printing speed, especially the optimization of speed gradient in weak areas, it is helpful to avoid the occurrence of defects such as cracks.

Refractory high-entropy alloys（RHEAs） are widely used in the aerospace field due to their excellent high-temperature performance. This study employs multi-wire arc additive manufacturing（M-WAAM） technology to fabricate Ta_1.5Mo_1.5Nb_0.5Zr₂Ti refractory high-entropy alloy. Using equipment such as optical microscopy（OM） and high-speed cameras, the influence rules of base current, peak current, and peak time ratio on forming quality are investigated. The optimal process parameters for preparing the Ta_1.5Mo_1.5Nb_0.5Zr₂Ti alloy are determined（base current 100 A, peak current 300 A, and peak time ratio 35%）. Metallographic characterization demonstrates that the fabricated components exhibit excellent forming quality, with unmelted area ratio below 10% and porosity less than 0.5%. To address the melting point differences among various wires, hot-wire technology is employed to facilitate the melting of high-melting-point Ta/Mo wires. For the first time, we propose a“single droplet pre-alloyed transfer”mechanism, elucidating the thermodynamic process of discontinuous liquid bridge transition and subsequent formation of a unified molten droplet from four simultaneously fed wires. Based on the thermodynamic mechanism of synchronous four-wire discontinuous liquid bridge transition forming a unified molten droplet, a“single droplet pre-alloyed transfer”mode is established. Parts deposited under this droplet transfer mode demonstrate good macroscopic morphology and fewer internal defects. Through force analysis of molten droplets, we establish a mechanical model incorporating key factors including gravity, electromagnetic force, and plasma flow force, demonstrating that synchronous non-continuous liquid bridge transition of four wires constitutes a sufficient condition for the formation of a unified molten droplet. Additionally, the developed bead width prediction model provides quantitative guidance for process optimization. This work establishes an important theoretical foundation for M-WAAM of RHEAs.

B₄C/TC4 titanium matrix composites are fabricated by laser-directed energy deposition（L-DED） to investigate the effect of B₄C content on the microstructure and mechanical properties of the deposited layers. The results indicate that during the deposited process, B₄C reacts in-situ with the TC4 matrix, generating TiC and TiB reinforcement phases. With the addition of B₄C content, the hardness of the composites increases significantly, while the plasticity decreases accordingly. When the mass fraction of B₄C is 0.2%, the precipitated phases of TiC and TiB exhibit the most uniform distribution. At this point, the composite achieves the highest strength while still maintaining good plasticity, demonstrating the optimal comprehensive mechanical properties. This performance optimization is mainly attributed to the synergistic effect of multiple strengthening mechanisms, including the load transfer effect of TiB phases with a high aspect ratio, the pinning effect of precipitated phases on grain boundaries and the resulting grain refinement.

As a critical strategic material for aero-engines and industrial gas turbines, the composition/process design, optimization and process control of superalloys remain at the core of industry concerns. The present work focuses on addressing practical challenges in the development and production of superalloys and their components. It identifies key influencing factors in typical processes within the manufacturing workflow and employs a combination of advanced characterization techniques such as synchrotron radiation and high-throughput experimental methods. This integrated approach enables the design and optimization of critical process parameters for superalloy manufacturing, thereby providing foundational support for enhancing process technology, product performance, research and development efficiency, and reducing costs. Taking representative manufacturing processes involving liquid-solid and solid-solid phase transformations as examples, we explore precision tailoring strategies and validation methods for key stages including master alloy melting/remelting, synergistic particle size/morphology control in gas atomization, shrinkage porosity control during casting solidification, powder storage/desorption treatments, powder consolidation through hot isostatic pressing（HIP） and heat treatment procedures. In addition, optimal usage conditions are investigated for auxiliary materials or consumables integral to superalloy production, particularly ceramics, isothermal forging dies and brazing repair materials. Notably, the research on process tailoring reveals significant phenomena: （1）the impact of oxygen existence forms in cast and powder metallurgy alloys; （2）the influence of the initial microstructural state of alloys on the phase transformation temperature during HIP consolidation and heat treatment; （3）the formation and control of abnormal phases and defects in cast, powder metallurgy and additive manufacturing alloys, along with repair materials for brazing and ceramic refractories. The aforementioned findings establish a theoretical foundation for optimizing and tailoring superalloy process parameters and achieving precise manufacturing control, while also providing feasible technical pathways for industrial implementation.

IN718 superalloy is extensively utilized in the aerospace and nuclear industries due to its outstanding oxidation resistance, heat-corrosion resistance, good structural stability, fatigue performance and safety reliability. It is one of irreplaceable materials for the hot-end components of next-generation advanced aircraft engines. Recently, laser powder bed fusion（LPBF） technology has developed as an innovative rapid prototyping technique, transcending the limitations of traditional shaping methods and structural designs. This technology has realized one-step laser near-net shaping of complex thin-walled structures, demonstrating substantial application potential. However, during the laser additive manufacturing process, the thin-walled surfaces are exposed to high laser input energy, which can readily induce warping, deformation, and even cracking, significantly impacting the service performance of these structures. To address these challenges, this work provides an overview of the working principle and recent advancements in LPBF technologies. It systematically analyses the multi-scale microstructural evolution and precipitation phase behavior of IN718 superalloy thin wall fabricated by LPBF. Special emphasis is placed on the initiation, propagation mechanisms and mitigation strategies for metallurgical defects, including optimized thin-walled structural designs, laser forming process parameters and alloy composition. In addition, the strengthening mechanisms underlying the mechanical properties of IN718 superalloy thin wall at both room and high temperatures are analyzed and discussed. Finally, the work summarizes the existing challenges such as insufficient critical performance under harsh conditions and future development directions of superalloy thin wall fabricated by LPBF, including establishment of laser forming process databases specialized for superalloy thin wall, investigation of solidification defect formation and novel control strategies in superalloy thin wall fabricated by LPBF, and optimization of the chemical composition design for high-performance superalloy thin-walled components.

With the rapid advancement of modern electronic and communication technologies, there is an increasing demand for high-performance electromagnetic wave（EMW）absorbing materials. Materials that combine lightweight properties, high-temperature resistance, and broadband absorption capabilities have become a growing research hotspot. This work proposes a novel strategy for fabricating ceramic metamaterials based on ultraviolet（UV）-curable hyperbranched polysilazane（UV-PSN） precursors. By introducing photosensitive groups into the ceramic precursor monomers and utilizing digital light processing（DLP） 3D printing technology, the synergistic regulation of microstructure and macroscopic morphology is successfully achieved. The fabricated SiCN ceramic metamaterials not only exhibit high-temperature resistance up to 1400 ℃ and tunable dielectric properties but also demonstrate excellent manufacturing precision. In addition, the unique hollow structure design significantly enhances the impedance matching performance of the overall SiCN ceramic material, achieving an effective absorption bandwidth of 3.4 GHz in the X-band. Furthermore, the overall weight of the SiCN ceramic metamaterials is reduced by 79.6% compared to solid structures. This study provides new design concepts and technical pathways for developing multifunctional EMW absorbing materials suitable for extreme environments.

“In-situ alloying” facilitates agile and swift adjustments to alloy compositions, thereby unlocking a multitude of prospects for developing novel alloys with distinctive microstructures. In this study, TC4-x316L alloys（with x=1%, 3%, and 5% by mass） are fabricated through the combination of selective laser melting（SLM） and the in-situ alloying approach. The effects of varying concentrations and SLM process parameters, including scanning rate and laser power, on the microstructural characteristics and mechanical properties of the alloys are investigated using metallographic microscopy（OM）, scanning electron microscopy（SEM）, XRD, and tensile testing. The results indicate that an increase in 316L content refines the alloy’s microstructure, causing the martensitic α′ phase to transform into the β phase. The alloy’s hardness initially rises and then decreases slightly, while its strength peaks at an x value of 1%. Specifically, when the laser power is set to 175 W and the scanning rate to 1000 mm/s, the TC4-1%316L alloy exhibits a yield strength of 1200 MPa, a tensile strength of 1425 MPa, and an elongation at break of 6.8%.

Thermoplastic composites（TPCs）have exhibited immense potential in aerospace applications, attributed to their exceptional toughness, weldability, recyclability, and efficient processing cycles. However, the manufacturing of complex structures is hindered by the high melting points and viscosities of their constituent resins. Resistance welding, leveraging Joule heating to induce interfacial melting and bonding, emerges as a viable alternative to mechanical fastening and adhesive bonding. This review delves into the fundamental principles underlying resistance welding, strategies for optimizing key process parameters, recent advancements in heating elements, and large-scale welding techniques, such as sequential and continuous resistance welding. The findings indicate that optimizing process parameters and improving heating elements can significantly enhance joint strength. To achieve engineering application of resistance welding technology, further research should be focused on process stability, reliability of welded joints, large-scale welding, and other issues.

Carbon fiber reinforced thermoplastic composite（CFRTP） is increasingly utilized in aerospace and automotive manufacturing sectors owing to its exceptional specific strength, strong toughness, and weldability. Induction welding stands as a pivotal method for fabricating typical CFRTP components. However, the intricate interplay of magnetic, thermal, and stress coupling during the induction welding process, along with its evolution and distribution characteristics, remains unclear, significantly impeding the cost-effective, efficient, and high-quality production of CFRTP components. In this study, a magnetic-thermal-mechanical coupling simulation model is developed for the induction welding of CFRTP stringer skin structures. This model is employed to investigate the distribution and evolution patterns of the magnetic field, temperature field, and residual stress field. The results show that under the influence of an alternating electromagnetic field, the magnetic field strength peaked at 1.45 mT in the component’s edge region. Notably, the simulated magnetic, temperature, and stress field all exhibit significant edge effects, which are intimately tied to the skin effect induced by high-frequency eddy currents. During welding, asymmetric and nearly elliptical high-temperature zones emerge on both sides of the skin’s bottom, with temperatures in proximity to the stringer area notably higher than those farther away. When the current frequency increases from 150 kHz to 250 kHz, the maximum stress of the induction joint increases from 637 MPa to 778 MPa, and the asymmetric stress concentration area at the welding interface expands accordingly. The measured temperature field and stress results are in high agreement with the simulation outcomes, effectively validating the model’s accuracy and applicability. This study offers theoretical backing for process optimization and quality control in the induction welding of intricate CFRTP components.

The resistance welding process of 7075 aluminum alloy（7075AA） and carbon fiber reinforced polyether ether ketone（CF/PEEK） is optimized through the activation of the aluminum alloy surface and its subsequent integration with a thermoplastic layer. A microgroove network is fabricated on the aluminum alloy surface using laser treatment, which notably augmented the mechanical coupling with the polyetherimide（PEI） thermoplastic layer. In contrast, the bonding effectiveness of sandblasted and untreated samples are inferior. Surface analysis conducted via Fourier transform infrared spectroscopy（FT-IR） and X-ray photoelectron spectroscopy（XPS） reveal the formation of Al—O—Si bonds and a silane coupling film transition layer, both of which fortified the interface. In the resistance welded joints, incomplete bonding between the sandblasted/laser-etched aluminum alloy and the PEI layer lead to debonding of the thermoplastic layer, which emerge as the predominant failure mode. The single lap shear strength（LSS） of the sandblasted joint is 10.47 MPa, whereas the LSS of the laser-etched joint attains 15.35 MPa. Following silane treatment, the bonding of the PEI thermoplastic layer is markedly enhanced, resulting in an LSS of 19.03 MPa for the laser-etched and silane-treated joint—a 23.97% increase compared to simple laser etching. At this juncture, the cross-section of the joint exhibites characteristics indicative of heating element fracture, with the failure mode transitioning to interlayer fracture.

This article provides an overview of the latest research status and application prospects of titanium/titanium alloy composite materials, highlighting their advantages in high specific strength, lightweight properties, thermal stability, and wear resistance, which position them as crucial materials in high-tech sectors such as aerospace, military equipment, and medicine. It summarizes research outcomes demonstrating the steady enhancement of mechanical properties, wear resistance, and thermal stability of titanium matrix composites through the addition of reinforcing phases. The review also reveals advancements in various processing technologies that have improved the grain structure and performance of these composites, while pointing out that challenges persist regarding the stability of these materials under high temperature and pressure conditions, as well as the bonding strength at interfaces. These issues necessitate the optimization of reinforcement distribution, bonding methods, and the exploration of novel composite systems. Furthermore, the combination of surface nanotechnology with digital simulation offers new avenues for optimizing the properties of titanium-based composites. Interface reinforcement and thermal stability research are identified as pivotal for future developments. Ultimately, the essay underscores that the enhancement of titanium-based composite properties and innovations in processing technologies are central to realizing their extensive application in extreme environments. This dual focus also constitutes the direction for pushing the boundaries of composite material performance even further.

Diamond-reinforced metal matrix composites, which exhibit unique properties of both metals and diamonds, are used as functional and wear-resistant materials in various fields. Additive manufacturing technology provides a novel approach for fabricating complex components of metal/diamond composites, significantly enhancing the design versatility of components. Based on several key additive manufacturing techniques, including selective laser melting, laser cladding and cold spraying, this paper introduces the research progress in the additive manufacturing of metal/diamond composites. It covers powder raw materials, core processing technologies and practical applications. Emphasis is placed on discussing the causes, consequenses and potential solutions for sputtering and diamond graphitization that may occur during the manufacturing process. Finally, the main challenges and future development directions of metal/diamond composites in additive manufacturing are summarized. The main manifestations are as follows: in the additive manufacturing process, problems such as diamond splashing, interface control between metal and diamond particles, graphitization of diamond and damage to diamond particles occur. The key issues to be addressed focus on optimizing the forming process to achieve coordinated control of the composite material’s density, interface bonding and diamond protection.

It provides theoretical guidance for the optimization of mechanical properties to research the dynamic shear mechanical properties and microstructural evolution law of laser-cladding Inconel 625（IN625） alloy. A series of dynamic shear experiments are conducted using the split Hopkinson pressure bar（SHPB）at varying ambient temperatures（20, 600, 800 ℃ and 1000 ℃）and strain rates（40000, 60000 s⁻¹ and 80000 s⁻¹）. These experiments aim to establish the dynamic shear stress-strain relationship. Pre- and post-loading morphologies and crystal structures of the alloy are characterized using scanning electron microscopy（SEM）and electron backscatter diffraction（EBSD）. The results show that both the strain rate strengthening effect and temperature softening effect are pronounced in laser-cladding IN625 alloy, with temperature softening effect predominantly influencing its mechanical behavior at elevated temperatures. Compared to the unloaded sample, the dynamic shear test at room temperature lead to the development of a prominent shear texture, with an increase in dislocation density and a decrease in average grain size. Specially, the proportion of small-angle grain boundaries increases from 29% to 85%. Conversely, high-temperature dynamic shear experiments, compared to room temperature loading, weaken the preferred orientation and reduce the dislocation density of the crystals. These high-temperature conditions further decrease the average grain size and lower the proportion of small-angle grain boundaries from 85% to 73.5%.

Light-curing 3D printing technology stands out as one of the oldest, fastest-growing and most widely used technologies in the field of 3D printing. This technology utilizes ultraviolet or other light sources to rapidly solidify liquid photosensitive polymers, creating products with complex geometrical structures that are difficult to achieve with traditional manufacturing methods. This paper summarizes the latest research progress in photocurable polymer materials for 3D printing, covering various types of photocurable polymers including thermoplastics with high remoldability, thermosets with good structural stability, and hydrogels with hygroscopic network cross-linking structures. Additionally, the applications of photocurable 3D printing polymers in various fields such as biomedical, flexible electronic devices, soft robotics, energy storage, and aerospace are discussed in detail. This review also explores the application of photocuring technology in 4D printing, highlighting the potential of 4D printing in dynamic materials and smart manufacturing. In the future, light-curing 3D printing technology is expected to advance toward the development of high-performance polymer composites, the integration of intelligent and automated printing systems, and the deep integration with cutting-edge technologies such as artificial intelligence, continually driving its applications and innovations in high-tech fields and advanced manufacturing.

The development of supersonic aircraft has created an urgent demand for heat-resistant aluminum alloy that can serve at the temperatures range from 300 ℃ to 500 ℃. However, the high-temperature mechanical properties of heat-resistant aluminum alloys are still unable to meet practical application requirements. Therefore, further research is needed from the aspects of material composition design and microstructure control to improve the comprehensive mechanical properties of heat-resistant aluminum alloys. In this paper, the research progress of heat-resistant aluminum alloys is reviewed from the aspects of microalloying design and eutectic alloys, and the development trend of heat-resistant aluminum alloys is prospected. The article first systematically introduces the development history and research status of Al-Sc, Al-Cu, Al-Si, and Al-Mg heat-resistant aluminum alloys, focusing on the microalloying design ideas of heat-resistant aluminum alloys, as well as the effects of transition metal elements and rare earth elements on precipitation phases, microstructure, and mechanical properties. Subsequently, the development status of heat-resistant eutectic aluminum alloys in Al-Fe, Al-Ni, Al-Ce, and Al-Si systems is comprehensively summarized, with a focus on the important role of rapid solidification technology and additive manufacturing technology in promoting the development of heat-resistant eutectic aluminum alloys. Finally, the main problems faced in the development and application of new heat-resistant aluminum alloys are analyzed, and the development trends of future research on heat-resistant aluminum alloy is discussed from the perspectives of data-driven composition design, high-throughput experimental verification, engineering application research, and standard system construction.

The three-layer structure molybdenum-silicon high-temperature oxidation-resistant coating was prepared on selective laser melting Ta10W alloy by slurry sintering process. The microstructure and element distribution of the Ta10W alloy and coating were characterized by SEM and EDS. The tensile properties, microhardness of the Ta10W alloy and coating, and the coating bonding strength were tested. The results show that the coating of selective laser melting Ta10W alloy is divided into three layers: outer, sub-outer and inner layers. The outer layer is TaSi₂ and MoSi₂ phases, the sub-outer layer is TaSi₂ phase and dispersed Ta₅Si₃ phase, and the inner layer is Ta₅Si₃ phase. The yield strength, tensile strength and uniform elongation of the coating and remove coating specimens are 639, 647 MPa, 13.6%, and 602 MPa, 675 MPa, 22.7%, respectively. Compared to the Ta10W alloy specimen, the uniform strain of the remove coating specimen is increased by 5.5%. The reason for this is that the thermal effect in the coating preparation process eliminates the residual stress of the Ta10W alloy formed by selective laser melting. The yield strength of the coated specimen is increased by 37 MPa due to the application of the coating. The microhardness of the outer layer, sub-outer layer, inner layer and Ta10W alloy were 550HV_0.2, 1120HV_0.2 , 534HV_0.01 and 307HV_0.2, respectively. The average coating bonding strength is 63 MPa, which is higher than that of the ceramic and high entropy alloy coatings. This is due to the fact that the three-layer coating has a good metallurgical bond to the Ta10W alloy.

The elliptic section body-centered tetragonal（E-BCT）lattice structure of 316L stainless steel fabricated based on selective laser melting（SLM）, represents an enhanced lattice structure with improved compressive performance. By optimizing the cross-sectional shape of the struts in the traditional body-centered tetragonal（BCT）lattice, the compressive properties of the lattice structure are significantly improved. Based on the mathematical model of the E-BCT lattice structure, the theoretical force model, and the Timoshenko beam theory, a relationship model is derived between structural parameters and relative density as well as effective elastic modulus. E-BCT lattice structures with varying semi-major axis lengths of the elliptical cross-section are fabricated using the SLM process, and static compression tests and finite element simulations are conducted. The study reveals that as the semi-major axis and shape factor of the elliptical cross-section increase, the performance of the E-BCT lattice structure improves significantly compared to the BCT lattice. The maximum improvement in effective elastic modulus is 637%, with average experimental and theoretical simulation errors of 6.5% and 5.1% respectively. The yield strength shows the maximum increase of 654%, with an average experimental and simulation error of 5.4%. Additionally, the specific stiffness and specific strength exhibit maximum improvements of 308% and 321% respectively.

The spot-welding defects of highly alloyed Ni-base superalloy GH4065A were investigated by using SEM and EBSD analysis methods. Effects of the welding defects on fatigue life and fracture behavior were studied by comparing thin plate samples with a central hole that were non-welded, densely welded and sparsely welded respectively. The results show that the lack-of-fusion defect, solidification crack and liquation crack are the main welding defects responsible for significant reductions in low-cycle fatigue life as well as combined low and high cycle fatigue life. These welding defects result in a transition of the fatigue crack initiation site from the inner surface of the central hole in the non-welded sample to the welding spot in the welded sample, leading to 44%-83% reductions in low-cycle fatigue life at 700 ℃/700 MPa. For the combined low and high cycle fatigue conditions（with a stress amplitude of 700 MPa for the low cycle loading part and 100 MPa for the high cycle loading part）, the welding defects not only alter the site at which fatigue cracks initiate, but also make the crack propagation mode more intergranular. This results in dramatic decreases of over 85% in the fatigue life of welded samples at both 600 ℃ and 700 ℃. Due to shorter distance between the welding spot and the central hole, densely-welded samples exhibit a slightly lower level of fatigue life under low-cycle loading conditions compared to sparsely welded samples. However, the fatigue life difference between them becomes negligible when subjected to combined low and high cycle loadings.

The damage evolution and failure process of pre-corroded additive manufacturing AlSi10Mg through in-situ tensile experiments under an optical microscope and micro-scale digital image correlation（μ-DIC） were investigates . Combining the microscopic deformation field evolution, material microstructure, three-dimensional corrosion morphology and fracture microscopic morphology to analyze the initiation and propagation of micro-cracks in pre-corroded AlSi10Mg. The results show that the stress concentration around the corrosion pits and subsurface defects（caused by the additive manufacturing process） leads to the initiation of micro-cracks. There are multiple micro-cracks initiating at the same time, and the propagation and coalescence of micro-cracks originated from the key damage regions dominate the final failure of the specimen. Material micro-structure and corrosion morphology have an important influence on crack propagation.

Additive manufacturing provides a new way to develop high-performance superalloys and components. A γ′- strengthened CoNi-base superalloy suitable for additive manufacturing was developed, and a crack-free block material was prepared by optimizing the parameters of electron beam melting（EBM） technology. The experimental results show that the lowest porosity of the alloy is about 0.14% when the scanning speed is 2000 mm/s. The microstructures of the as-printed CoNi-base alloy are columnar grains growing along the <001> direction, the average grain width is about 235 μm, and the volume fraction of γ′ phase is about 30%. After hot isostatic pressing and solution aging treatment, the porosity of the alloy is further reduced to about 0.09% with unobvious change of columnar grains. The average size of γ′ phases is about （70±18）nm with the volume fraction of about （32±3.6）%. The results of room temperature tensile tests show that the additive manufactured γʹ-strengthened CoNi-base superalloy exhibits excellent strength and ductility, showing a good potential of industrial application.

Introducing emerging high entropy alloys materials into advanced intelligent manufacturing for laser additive repair is expected to promote the deep integration of new generation of materials and manufacturing technology and greatly improve the utilization of raw materials and energy, which have broad application fields and excellent development prospects. This paper introduces the application status of high entropy alloys in laser additive repair, and points out that the mismatch of strength and toughness, inaccurate performance control and unclear strengthening mechanism are the key scientific problems that need to be solved urgently in the expansion and application of high entropy alloys in laser additive repair. Exploring the ductile-brittle transition mechanism of the high entropy alloys cladding coating metal, clarifying the basic mapping relationship among the materials, processes, microstructure and coating performance of cladding coatings, obtaining a complete and effective method for predicting the composition of high entropy alloys, innovating the design of alloy powder system, optimizing and adjusting the control processes, and obtaining a high-performance cladding coating suitable for extreme service environment and with low cost are the main research focus and development trends in the future.

Selective laser melting（SLM）can achieve nearly net-shape complex parts of GH3536 alloy, and its high temperature mechanical properties are important indicators for safe service. The effect of heat treatment on microstructure and high temperature tensile properties of SLM GH3536 alloy were studied. The heat treatment at 1225 ℃ for 1 h was carried out to explore the regulation mechanism of microstructure and properties. The results show that heat treatment can effectively eliminate the cellular subgrain structure inside the grains, which significantly enhances the dislocation slip ability. The tensile elongations at room temperature, 650 ℃ and 815 ℃ are increased by 75%, 92% and 683%, respectively. In addition, the decrease of the aspect ratio of the columnar grains significantly reduces the anisotropy in the heat-treated sample. The fracture analysis shows that the fracture mode of the heat-treated sample changes from intergranular fracture to mixed fracture with the increase of tensile environment temperature.

Key components used in the high-pressure compressor of advanced aero engines operating in the 550-600 ℃ range have an urgent demand for 600 ℃ high-temperature titanium alloy. However, the use of casting, forging, and other traditional processing techniques is not sufficient to meet the requirements for gradient or composite structures, functional integration components and complex components that are difficult to form. Additive manufacturing is an advanced manufacturing technology that offers unique advantages such as material design-manufacturing integration and complex design-customization integration. It provides a new approach to the development of new materials and technologies of 600 ℃ high-temperature titanium alloy. Currently, attention is being paid to the processing of 600 ℃ high-temperature titanium alloy by using additive manufacturing techniques at home and abroad, focusing on the relationship among materials, processing, structures, and properties. Firstly, this paper reviews the research on 600 ℃ high-temperature titanium alloy in brief, introduces the microstructure characteristics of deposited and post-treated states of 600 ℃ high-temperature titanium alloy under different additive manufacturing processes, and analyzes key properties such as tensile properties, creep properties, thermal fatigue properties, and antioxidant properties. Then, the research progress of composite materials based on 600 ℃ high-temperature titanium alloy and gradient structure built by additive manufacturing is discussed. Finally, the prospects are provided for research directions including the development of 600 ℃ high-temperature titanium alloy materials for additive manufacturing, exploration of hybrid manufacturing processes, defect control, and establishment of performance evaluation standards.