MXene, as a typical two-dimensional transition metal carbide/nitride, exhibits broad application prospects in intelligent electromagnetic fields owing to its exceptional electrical conductivity, tunable interlayer spacing and rich surface functionalization. This review systematically summarizes recent advances in the synthesis, performance modulation strategies and research progress of MXene-based composites within the domain of electromagnetic functional materials. Firstly, it introduces the fundamental structural and electronic characteristics of two-dimensional MXene and critically examine prevailing synthesis routes alongside the resulting microstructural features of MXene-based composites. Secondly, it deeply explores the performance control strategies for these composites, elucidating the underlying mechanisms of multidimensional interfacial optimization—including tailored structural design, targeted surface functionalization and synergistic hybridization. Finally, in response to the key challenges currently faced by MXene-based composite, such as inadequate environmental stability, underdeveloped scalable manufacturing protocols and difficulties in achieving balanced multifunctional integration—it proposes promising future research directions to facilitate their translation into high-end applications, particularly in aerospace and related advanced technological fields.

Radar and infrared stealth materials play a crucial role in enhancing the stealth performance of equipment. In recent years, vanadium-based oxides have shown broad application prospects in the field of radar and infrared stealth due to their unique thermochromic phase transition properties and excellent infrared radiation modulation capabilities. This paper summarizes the research progress of vanadium-based oxide radar and infrared stealth materials at home and abroad. From three dimensions of multi-component design, structural regulation and element doping modification, it systematically elaborates on the performance optimization methods and mechanisms of vanadium dioxide, vanadium trioxide and vanadium pentoxide-based stealth materials. Furthermore, this paper proposes five key directions for future research on vanadium-based oxide stealth materials: (1) the design of new heterostructure, which aims to overcome the inherent defects of vanadium-based oxides through structural regulation to enhance stealth performance; (2) artificial intelligence-assisted material design, which will utilize machine learning to model the composition-structure-performance relationships and accurately predict performance parameters, thereby shortening the material development cycle; (3) the synergistic optimization of multiple loss mechanisms, intended to couple conductive loss, dielectric loss and magnetic loss for synergistic enhancement, maximizing the improvement of stealth performance; (4) the characterization of complex interfaces, which focuses on strengthening interface characterization to reveal the wave-absorbing mechanism of composite systems in view of the complex interfaces caused by rich valence states; (5) broadband adaptive stealth, which involves developing stealth materials with both broadband and adaptive response capabilities based on thermally induced phase transition characteristics.

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.

Adaptive thermochromic materials can meet the requirements of military dynamic camouflage application in the visible light band. However, a single thermochromic material is not suitable for the development of the battlefield as the requirements of the battlefield multi-band camouflage increase, especially the development of radar-band camouflage. Therefore, thermochromic/radar compatible technology is the issue that needs to be addressed. Adaptive thermochromic microcapsule materials are prepared by in-situ polymerization. The composition of microcapsule is analyzed using SEM, XRD and FTIR. The absorption properties of microcapsule, radar absorbing and thermochromic-radar composite materials are tested using coaxial method. The microcapsule materials are composed of thermochromic complex (fluorescent alkane dyes, bisphenol AF, dodecanol and conjugated color change substances) and urea formaldehyde resin. The corresponding thermochromic coating material includes thermochromic microcapsules, waterborne polyurethane and additives, which are compatible with each other. The microwave absorption test shows that the imaginary part of permittivity and permeability in thermochromic coatings are both zero, which possesses non-electrical and magnetic lossy properties, and does not significantly affect the wave-absorbing performance of the radar-absorbing coatings. The newly developed thermochromic coating material is a transparent to microwave due to the low electromagnetic loss capability. Finally, the thermochromic coating achieves excellent compatibility with radar stealth coatings.

Graphene oxide (GO) is used as the substrate material and MgCl₂ is used as the catalyst. Under a mixed atmosphere of N₂ and NH₃, GO is converted into reduced graphene oxide (RGO) by chemical vapor deposition. Meanwhile, collapse boron nitride nanotubes (CBNNTs) are grown on its surface to synthesize RGO/CBNNTs composite materials. By controlling the reaction temperature (800, 850, 900 ℃), the generation of by-product MgF₂ can be effectively inhibited and the growth of the inner diameter of CBNNTs tube wall can be controlled, thereby preparing three types of RGO/CBNNTs composite materials. The wave absorption performance of RGO/CBNNTs composite in the 2-18 GHz frequency band is investigated by attaching CBNNTs of different pipe diameters to the surface of RGO. Among them, the absorption performance of RGO/ CBNTS-900 is the best. According to the test data, at 13.36 GHz, the minimum reflection loss (RL_min) of RGO/ CBNTS-900 reaches −49.17 dB, and the matching thickness is only 1.59 mm. All the above parameters are stronger than those of RGO. Due to the high electrical conductivity and large dielectric constant of RGO, it is extremely prone to causing electromagnetic impedance mismatch problems. The introduction of CBNNTs has reduced the ε' of RGO from 7.7 to 5.1, alleviating the problems of high electrical conductivity and large dielectric constant of RGO, and improving the microwave absorption performance. This method provides a new idea for the application of RGO materials in the field of microwave absorption.

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.

Due to their excellent mechanical properties, dot matrix structures show a broad application prospect for spacecraft lightweight structures and cushioning energy absorbing devices. In this paper, two hybrid structures based on octagonal bipyramidal structure and Kelvin structure are proposed, and the corresponding dot matrix structures are prepared by selected laser melting. The mechanical properties, energy-absorption characteristics and deformation mechanisms of the hybrid structures are systematically investigated through experiments and simulation. It shows that the mechanical and energy-absorbing properties of the hybrid structures are significantly enhanced; when the relative density is the same, the energy-absorbing efficiency of the hybrid structure 1 is increased by 15.7%, and the specific strength and specific energy-absorption of the hybrid structure 2 are increased by 93% and 92%, respectively. In terms of the deformation mechanism, the hybrid structure 1 uniformly collapses, which shows a bending-dominant deformation mechanism; while the hybrid structure 2 collapses layer by layer throughout the whole process from bottom to top. In order to further improve the deformation mechanism and enhance the mechanical properties of the hybrid structure, the geometric parameters of the hybrid structures are investigated. It is found that adjusting the ratio of inner and outer rod diameters can realize optimization of the hybrid structure. When λ = 0.75, comprehensive performance of hybrid structure 1 is best, with in its specific strength and specific energy absorption increasing by 21% and 10% respectively.

2.5D woven composites show great promise for aerospace applications owing to their high specific strength, high specific modulus and good delamination resistance. However, there is a dearth of research on their mechanical properties and failure behaviour at high temperature environment. This paper presents numerical simulation and experimental study on the quasi-static tensile mechanical response and failure behaviour of 2.5D woven C_f/Al composites at high temperature (400 ℃). Representative unit-cell models at the micro- and meso-scale are constructed based on the microstructure and periodic arrangement characteristics of the yarn. Based on the temperature-related material parameters of the matrix and interface, a multiscale finite element model is established to numerically analyse the thermal stress distribution as well as macroscopic and mesoscopic mechanical behaviour of the composites at high-temperature environment. The high temperature induces inhomogeneous thermal stress distribution in the composites, where the matrix and yarns are subjected to compressive and tensile stress, respectively. The experimental results show that the tensile modulus, ultimate strength and elongation of the composites are 63.7 GPa, 238 MPa and 0.72%, respectively. The numerical tensile stress-strain curve is generally consistent with the experimental results. Numerical simulation results show that the matrix and interface damage that induced by the thermal stresses accumulates and expands gradually during the tensile process. This results in the emergence of local interface debonding at the initial tensile stage. As the tensile strain increases, the composites successively experience the local failure of warp yarns and transverse cracking of weft yarns. At the final stage, the severe axial fracture of warp yarns leads to catastrophic fracture of the composite, resulting in a dramatic drop of the tensile stress curve. The fractured warp yarn exhibits a rough fracture surface with the characteristics of fibre pull-out and matrix alloy tearing.

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.

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.