SiC_f/SiC composites have broad prospects for application in aerospace high-temperature components due to their low density， excellent high-temperature mechanical properties， and oxidation resistance. However， residual stresses generated during preparation and service severely restrict their performance. This paper systematically reviews the research progress on residual stresses in SiC_f/SiC composites. Firstly， the formation mechanisms of micro-residual stresses and lattice distortion stresses are elaborated， and the coefficient of thermal expansion mismatch， phase transformation volume effect， and process-induced effect are identified as the main causes. Secondly， the principles， advantages， and disadvantages of experimental characterization techniques （including X-ray diffraction， neutron diffraction， Raman spectroscopy， and nanoindentation） and numerical simulation methods （such as finite element method and molecular dynamics） are introduced. Then， the regulation mechanisms of residual stresses on the mechanical properties， environmental stability， and functional characteristics of composites are analyzed， and residual stress regulation strategies through temperature gradient control， interface coating design， and heat treatment are summarized. Finally， it points out that the current frontier challenges include stress dynamic reconstruction in ultra-high temperature oxidation environments， in-situ real-time monitoring of residual stresses under complex loads and thermal cycles， and artificial intelligence-driven residual stress prediction and optimization design.

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.

The complexity of cavities， randomness of pore distribution， and multi-scale of pore size in porous materials make it difficult to quantitatively characterize pore microstructure. In recent years， fractal theory attracts more attention because of its unique advantages in portraying the self-similarity and multi-scale of complex structures. This paper reviews the development roadmap of fractal theory and its applications on porous materials， analyzes the single and multi-fractal feature extraction and characterization methods for porous materials at different scales， summarizes some advanced engineering material applications based on multifractal optimization， and discusses the research progress in the applications of fractal theory to the characterization of mechanical， thermal and permeability properties of porous materials. During the optimization design and performance characterization process of porous materials based on fractal theory， the main issues and shortcomings including the ambiguity of correlation mechanism between micro structure and macro multi-functional characteristics， and low efficiency and accuracy for prediction models and/or optimization algorithm are pointed out. The development trend and potential engineering applications of fractal theory such as the consideration of cross-scale effect， multi-physics coupling analysis， and optimization strategy based on machine learning are prospected.

In the semiconductor industry， temperature control is of paramount importance， yet numerous research challenges persist， such as the selection of thermal control materials and the design of heat dissipation management systems. The development of flexible electronic films is also a significant challenge. Currently， flexible electronic films based on graphene and carbon nanotubes are hindered by high costs， limiting their widespread application. Therefore， the development of carbon black flexible electronic films with excellent heating performance， a broad temperature regulation range， and suitability for large-scale applications is of considerable significance. To determine the optimal carbon black loading， this study fabricates composite films with varying carbon black contents and conducts a series of tests， including percolation threshold， maximum temperature， rapid thermal response， cyclic heating stability， and tensile performance tests. The experimental results indicate that the percolation threshold of carbon black in the polymer matrix is approximately 20%. The temperature regulation range of the carbon black heating films is between 25 ℃ and 60 ℃. Under a 32 V voltage， films with 50% and 55% carbon black content reaches maximum temperatures of 53.9 ℃ and 60 ℃， respectively. Both films demonstrate not only a broad regulation range but also excellent thermal stability after cyclic heating， along with superior mechanical properties.

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.

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.

The rotating bending fatigue behavior of 9310 steel by vacuum carburization heat treatment is studied， the microstructure and fracture morphology are analyzed. The hardness gradient， surface roughness， residual stress distribution， and inclusion size in the carburized layer are characterized. Based on the Murakami three-dimensional defect model， a fatigue limit prediction method coupling carburized layer hardness， residual stress， inclusion size， and surface roughness is established， thereby revealing effective approaches to enhance the fatigue performance of vacuum carburized specimens. The results show that after vacuum carburizing heat treatment， the carburized layers of specimens tempered at 150 ℃ and 180 ℃ exhibit a dispersed distribution of carbides and uniform， fine martensite， with no oxidation or decarburization on the surface. Cracks mainly originate from non-metallic inclusions. Among them， the specimen tempered at 150 ℃ possesses a higher surface hardness of 755HV， an effective hardened layer depth （d） of 1.20 mm， and a peak residual compressive stress of 465 MPa. Cracks primarily initiate from non-metallic inclusions. The predicted fatigue limits for specimens tempered at 150 ℃ and 180 ℃ are 1275 MPa and 1260 MPa， respectively， which deviate from the measured values（1282 MPa and 1242 MPa） by only 0.5% and 1.4%， indicating that this prediction method exhibits excellent applicability to carburized steel materials. The effective approaches to improve the fatigue performance of vacuum carburized specimens include reducing inclusion size， increasing carburized layer hardness and residual compressive stress， and lowering surface roughness.

This study systematically investigates the non-isothermal curing kinetics of bismaleimide resin EC230R using non-isothermal differential scanning calorimetry （DSC） in conjunction with the Flynn-Wall-Ozawa （FWO） model and the Málek method. The FWO analysis reveals that the apparent activation energy of the resin system exhibits a rapid nonlinear rise when the conversion rate exceeds 0.8. This transition indicates a dynamic shift from a chemically controlled reaction phase to a diffusion-controlled phase. Based on Málek kinetic modeling， the global reaction rate equation is derived to construct the rate equation for the isothermal curing process. This model enables the prediction of curing behavior and conversion rate of bismaleimide resin EC230R at different temperatures. Furthermore， the curing process is optimized using the curing kinetics model of bismaleimide resin， and the thermal and mechanical properties of the cured bismaleimide resin EC230R are characterized and verified via non-isothermal scanning， tensile， and flexural testing. The results show that after curing at 250 ℃， the conversion rate increases by 14%， and the glass transition temperature （T_g） of the resin increases by 30%， while the tensile modulus and flexural modulus decrease slightly by 9.8% and 7.2%， respectively. A strong positive correlation is observed among T_g， curing temperature， and conversion rate， suggesting that high-temperature curing enhances thermal resistance by increasing crosslink density. However， excessive crosslinking restricts segmental mobility and reduces packing density， leading to modulus reduction. This study provides critical guidelines and experimental validation for optimizing curing processes and developing high-temperature-resistant structural materials based on bismaleimide resins.

Ti₂AlNb alloys，as representative TiAl-based alloys designed for long-term use in the temperature range of 650-750 ℃，exhibit promising potential for applications in typical aero-engine components. However，their susceptibility to oxide scale instability，interfacial embrittlement，and degradation of mechanical properties under high-temperature oxidation，molten-salt corrosion，and water-vapor environments constitutes one of the key factors restricting their practical engineering application. The Ti₂AlNb alloy primarily consists of O，B2，and α₂ phases，introducing a high density of grain boundaries and phase interfaces within the alloy，accompanied by pronounced compositional partitioning and electrochemical heterogeneity. As a result，Ti₂AlNb alloys exhibit significant interface sensitivity and non-uniform environmental responses under complex working conditions. This review paper focuses on the significant role of the multiphase microstructure in governing high-temperature oxidation and corrosion behavior and systematically summarizes the research progress on Ti₂AlNb alloys. Particular emphasis is placed on the formation and evolution of complex oxide scales characterized by TiO₂，Al₂O₃，and Nb-related oxides. The dual role of Nb in regulating oxygen diffusion and determining oxide types is clarified，and the effects of selective oxidation among different phases and the associated interfacial stress concentration on the long-term stability of oxide scales are discussed. Considering complex working conditions，this work outlines the coupled corrosion-oxidation behavior of Ti₂AlNb alloys in molten salts containing Cl^－ and SO{}_{\mathrm{4}}^{\mathrm{2}-} as well as in water-vapor atmospheres. It clarifies the localized corrosion sensitivity arising from the electrochemical differences between the B2 and O phases， the destructive effects of corrosive ions such as Cl⁻ and SO{}_{\mathrm{4}}^{\mathrm{2}-} on the continuity and compactness of the oxide scale， and the critical impact of hydrogen ingress-induced intergranular embrittlement in water vapor on application reliability. On this basis，various surface protection technologies developed in relation to the multiphase microstructure and the active diffusion behavior of Nb are introduced. These include aluminizing treatments that construct α-Al₂O₃-dominated selective oxide scales，silicide and Si-rare-earth composite coatings that form SiO₂ barrier layers，and MCrAlY-type metallic coatings with diffusion-barrier designs. The stability of coating/substrate interfaces under complex interdiffusion conditions is also analyzed. From the perspective of engineering applications，key challenges remain in understanding multi-interface coupled oxidation and corrosion mechanisms，establishing reliable long-term environmental stability evaluation methods，optimizing integrated coating-system design，and improving service-life prediction. Future research focuses on multiphase interface regulation and the synergistic design of advanced protection systems.