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

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

Mechanical metamaterials achieve extraordinary mechanical properties beyond those of natural materials by leveraging structural topology， multi-material integration， and multiscale design. These artificial systems offer promising solutions to overcome the intrinsic limitations of conventional materials， enabling their application in demanding fields such as aerospace， deep-sea exploration， and intelligent equipment. In recent years， driven by innovations in physical mechanisms， design strategies， and manufacturing techniques， the field has rapidly evolved from focusing on single-function materials to multifunctional， programmable， and stimuli-responsive systems. Unlike traditional metamaterials with static and singular mechanical responses such as low-frequency vibration isolation， negative Poisson’s ratio， or directional stiffness， multifunctional mechanical metamaterials enable dynamic control of force–displacement behavior， Poisson’s ratio， and wave propagation through structural reconfiguration. This review summarizes recent advances in the design and application of multifunctional mechanical metamaterials with intelligent responsiveness. We focus on the development of quasi-zero stiffness structures， auxetic systems， and bandgap-tunable lattices， emphasizing their programmability and multimodal responses under external fields. Finally， future perspectives are discussed， including the need for highly integrated unit cell designs， in-situ adaptive modeling under multiphysics coupling， and the exploration of novel physical principles， smart materials， and advanced manufacturing technologies. These efforts aim to shift the paradigm of mechanical metamaterials from passive architectures to active， intelligent systems suitable for complex service environments.

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

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

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

Digital light processing （DLP） technology has attracted significant attention for its ability to quickly form complex structure porous silicon nitride （Si₃N₄） ceramics without the need for molds. However， challenges still exist regarding the rheological properties， stability， and curing performance of the Si₃N₄ ceramic slurry. This paper successfully enhances the rheology and curing performance of Si₃N₄ slurries by optimizing the multi-component photosensitive resin， dispersant system， and photocuring forming parameters. The results show that the multi-component resin system consisting of HDDA， TMP3EOTA， and ACMO at 3∶1∶2 mass ratio achieves optimal performance. Compared to the system containing IBOA， ACMO has no strong conjugated groups， and its morpholine ring can stabilize the free radicals of photoinitiators， achieving 95% increase in curing depth of the Si₃N₄ slurry. After the introduction of the dispersant Solsperse 41000， the stability and rheological properties of the slurry are further improved. As the content of Solsperse 41000 increases， the viscosity of the Si₃N₄ slurry first decreases and then increases； when the dispersant content reaches 3% of the powder mass， the slurry viscosity drops to its minimum value （0.16 Pa·s）. However， the addition of an excessive amount of dispersant will lead to multi-layer adsorption on the powder surface and self-entanglement of the dispersant itself， which impairs the rheological properties of the slurry. Based on the above optimizations， adjusting the laser power and exposure time to 15 mW/cm² and 7 s， respectively， can simultaneously meet the requirements for both curing depth and forming precision. Finally， Si₃N₄ ceramic green bodies with complex structures are successfully printed， and a porous Si₃N₄ ceramic with porosity of 18.76% and flexural strength of 240.28 MPa is ultimately produced. This study provides an experimental basis for the preparation of high-performance porous Si₃N₄ ceramics.

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

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

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

In order to improve the fracture toughness of Y₂O₃ ceramics and realize the preparation of complex structures， Al₂O₃ whiskers （Al₂O_3w） are introduced to toughen Y₂O₃ ceramics， and Al₂O_3w/Y₂O₃ complex ceramic parts are successfully prepared by binder jetting method. The effects of Al₂O_3w content （1%， 3%， 5%，mass fraction，the same below） on the properties of green body forming， sintering densification， and mechanical properties are systematically investigated. The results show that the addition of Al₂O_3w has a little effect on the porosity of the green body， but significantly optimizes the sintering process. When the content of Al₂O_3w is 3%， the porosity of the sintered ceramics is as low as 57.47%， the flexural strength is enhanced to 6.54 MPa. The fracture toughness reaches 2.31 MPa·m^1/2， which is 2.9 times higher than that of pure Y₂O₃. Excessive addition （5%） results in a rise in porosity to 59.47% and a decrease in fracture toughness to 1.54 MPa·m^1/2. Microanalysis shows that Al₂O_3w inhibits crack propagation through the whisker-bridging and crack-deflection mechanism， with an optimal doping amount of 3%.

As a one-dimensional single-crystal material，silicon nitride whiskers possess excellent mechanical，thermal，high-temperature resistance，and corrosion resistance properties，making them a widely used reinforcing material. This paper systematically reviews the current status and application prospects of silicon nitride whisker-reinforced polymer，metal，and ceramic matrix composites. This work introduces the mainstream methods for preparing silicon nitride whiskers，including self-propagating high-temperature synthesis，carbothermal reduction nitridation，direct nitridation，and high-temperature heat treatment. The advantages and disadvantages of each method are analyzed，and the challenges and solutions in practical applications，such as interface bonding and dispersion uniformity，are discussed. Additionally，the paper also provides an outlook on the future development prospects of whisker preparation and application.

With the advancement of high-performance aero-engines and the growing future requirements for intelligent engine design， monitoring the strain of critical components subjected to combined thermal and mechanical stresses has evolved as a vital data source. This data is essential for evaluating material performance during service， enhancing design accuracy， and achieving comprehensive lifecycle management.Indium tin oxide （ITO） thin films have emerged as a preferred material for measuring high-temperature strain in structural materials due to their stability at elevated temperatures，excellent strain measurement sensitivity，and excellent electrical conductivity. This paper expounds on the fundamental principles，basic structures，and preparation methods of resistive thin-film strain gauges，and analyzes and investigates strategies for enhancing the performance of ITO resistive thin film strain gauges，thereby promoting their engineering applications in the aerospace industry.

Phenolic resin materials have a wide range of applications in aerospace thermal protection due to their excellent thermal stability， as well as their low cost and short preparation cycle. By means of chemical and physical modification， more functions or new features can be integrated into phenolic resin matrix composites to make them develop in the direction of high performance and further broaden their application areas. In this paper， the research progress of heat-resistant modification of phenolic resin matrix composites in recent years is reviewed in detail， and the modification methods for synthetic raw materials， molecular structure， and pyrolytic morphology are discussed from the thermal decomposition mechanism. The application prospects are elaborated， and the current problems are analyzed in depth， such as the performance needs in extreme environments still need to be further improved， and the development direction of the high performance and multifunctionality of phenolic resin matrix composites is proposed， and the development direction of further improving its serviceability is discussed. The development direction of high performance and multifunctionalization of phenolic resin matrix composites is proposed， which is of great significance for further improving its service performance and expanding its application scope.

Nanoscale zero-valent iron （nZVI） is used for the reductive degradation of nitrate wastewater due to its advantages， such as abundant elemental content， strong reducibility， and easy recoverability. However， its surface is prone to passivation， making efficient reactions difficult to sustain. The reaction is highly dependent on an acidic environment and has poor selectivity toward target reactants. The products of its reaction with nitrate wastewater are often dominated by toxic ammonia nitrogen. For this reason， numerous researchers have conducted studies focusing on the efficient reaction between nZVI and nitrate wastewater to generate pollution-free nitrogen gas. This paper first elaborates on the mechanism of nitrate wastewater degradation by nZVI alone and highlights its limitations. It then summarizes the enhancement measures to improve the nitrate-degradation efficiency and nitrogen-generation rate of nZVI. The summary shows that the key to improving the nitrate degradation efficiency of nZVI lies in providing sufficient protons and reducing the negative impact of oxides. The main measures to increase the nitrogen yield include three aspects. First is the modification of the chemical properties or structure of nZVI itself. Second is the addition of reducing additives. Third is the coupling with other processes. Finally， this paper comments on and prospects various measures for enhancing the efficient degradation of nitrate wastewater by nZVI.

Al-Si-Mg-Sc-Zr alloys are prepared through phase diagram design and the smelting process. The effect of elemental addition levels on solidification parameters is investigated. Additionally，the room-temperature tensile properties and microstructure of the as-cast alloys are thoroughly analyzed.The results reveal that the as-cast microstructure consists of α-Al matrix， Al-Si eutectic phase， Mg₂Si phase， Al₃Zr phase， and Al₃（Sc， Zr） phase. Silicon has the most pronounced effect on the tensile strength， whereas magnesium primarily influences the secondary dendrite arm spacing（SDAS）. The liquidus temperature gradually decreases with an increase in silicon content， and the solidus temperature continuously drops as the magnesium content rises.With the addition of the Sb element， the morphology of the eutectic silicon phase transforms from needle-like and long-striped shapes to short rod-shaped or worm-shaped forms， and its aspect ratio decreases from 8.19 to 3.31. The fine-sized Al₃Zr and Al₃（Sc， Zr） phases refine the grain size from 272 μm to 224 μm. As a result， the ultimate tensile strength and yield strength reach 211 MPa and 125 MPa， respectively， with an elongation of approximately 5.1%. The enhancement of mechanical properties is attributed to the fine-grained strengthening of the Al₃Zr and Al₃（Sc， Zr） phases， as well as the second-phase strengthening effect of the eutectic silicon phase. As the addition of silicon and magnesium elements increases， the fracture mechanism shifts from a combination of intergranular and dimple fractures to purely intergranular fractures.

Porous metal aluminum， a low-density metallic foam with a porous structure， exhibits good energy absorption and sound absorption properties， leading to its wide application in fields such as machinery manufacturing and aerospace. Currently， the fabrication of porous aluminum primarily relies on physical or electrochemical methods， which often involve complex processes and high costs. This study employs a low-cost material extrusion forming technique to prepare porous metal aluminum， investigates its forming characteristics， and systematically examines the effects of aluminum-based slurry solid content， forming parameters， and sintering processes on the properties of the extruded porous metal aluminum， and the pore structure is optimized to prepare porous metal aluminum. The results show that when the solid content of the aluminum-based slurry is 80%（mass fraction）， the desired billet can be extruded completely without collapse or depression. Using process parameters of a needle diameter of 0.34 mm， a layer height of 0.22 mm， and a filling rate of 50% to prepare the billet. The porous metal aluminum obtained by sintering at 650 ℃ and holding for 150 min has good properties， with a flexural strength of 12.57 MPa， a porosity of 53.96%， and a shrinkage rate of 3.19%， meeting the performance requirements for porous metal aluminum.

The hot isostatic pressing （HIP） technique is employed to create a diffusion-bonded joint between DD15 alloy and SC-4 alloy. This study systematically examines the impact of HIP temperature and nickel electrodeposited coating on the microstructure and elemental diffusion characteristics at the diffusion-bonded joint. The results reveal that HIP diffusion bonding effectively achieves a reliable bond between DD15 and SC-4. Both sides of the bonding interface exhibit distinct element diffusion zones and microstructure affected zones， accompanied by the precipitation of large γ' phases， carbides， and oxides in proximity to the interface. In the DD15 alloy， recrystallization occurs in a region approximately 10-20 μm from the surface. Carbides and large-sized γ' phases are present within this region. In the range of 20-140 μm away from the interface， the γ' phases undergo coarsening. For the SC-4 alloy， carbide redissolution occurs within 30 μm from the interface， and large γ' phases are observed in the vicinity of the interface.As the HIP temperature increases， the microstructure of DD15 within the heat-affected zone remains relatively unchanged， whereas the prominent γ' phase in SC-4 diminishes， and the size of carbides and oxides at the bonding interface augments. The influence of nickel plating is evident， with various shapes of γ' phases （long strip-shaped γ' phase， large γ' phase （>2 μm）， fine γ' phase （200-500 nm）） emerging near the connection interface， accompanied by the disappearance of carbides and oxides. Notably， the large γ' phases in SC-4 also vanish under this condition.

In light of the application scenarios where the combustion chamber and turbine components of aeroengines are repeatedly subjected to short-term overheating， and reusable spacecraft endure cyclic high-temperature conditions， an experimental study is conducted to investigate the effects of cyclic overheating on the tensile properties of GH3230 alloy. Additionally， the oxidation-related microstructural and compositional changes are characterized.The results reveal that the cracking of internal oxides during plastic deformation reduces the actual load-bearing area of the oxidized sample. Grain coarsening also occurs during thermal exposure. These two factors jointly contribute to a continuous decline in room-temperature tensile strength as the number of overheating cycles increases. After removing the surface layer， the tensile strength is restored to a certain degree. The oxidative decarburization zone that forms near the sample surfaces exhibits improved plastic deformability. As a result， it effectively blunts oxide cracks and prevents them from penetrating into the matrix. Consequently， the tensile elongation of the oxidized sample after 10-40 cycles of over-temperature remains at relatively high levels due to the avoidance of the notch effect caused by surface cracks.

To develop a high temperature shape memory alloy with high transformation temperature and good cold-working ability，NiTiTaHf wires with a diameter of 0.2 mm are fabricated through cold drawing and subsequent annealing.The influence of annealing temperature on microstructure，martensitic transformation and superelasitic behavior of NiTiTaHf wire are investigated. The results show that the superelasticity of NiTiTaHf wire is quite sensitive to the annealing temperature. The sample annealed at 500 ℃ displays the substantial superelasticity featuring a recoverable strain of 7.6% over a broad temperature range from 20 ℃ to 200 ℃. In contrast，the sample annealed at 700 ℃ only shows a small superelastic recoverable strain （less than 3.3%）over a narrow temperature range （140-200 ℃）.This difference in superelastic behavior is caused by the change of grain size resulting from the different annealing temperature，the grain size of the sample annealed at 500 ℃ is about 12 nm. This leads to the occurrence of strain glass state in the sample and the resultant superelasticity over a wide temperature range.

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

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

The microstructural evolution and yield strength changes of medium-Mn steels with Cu， Ni， and Cu/Ni composite additions after aging at 500 ℃ are systematically compared using electron backscatter diffraction （EBSD）， transmission electron microscopy （TEM） with energy-dispersive spectroscopy （EDS）， and mechanical property tests. The precipitation strengthening mechanism is further revealed. The results show that aging at 500 ℃ increases the yield strength by approximately 125， 540 MPa， and 575 MPa for the Cu， Ni， and Cu/Ni alloyed steels， respectively， due to precipitation strengthening. The strengthening effect in the Ni and Cu/Ni alloyed steels is much greater than that in the Cu alloyed one， mainly because the number of precipitated nanoparticles in the former two steels is much greater than that in the Cu alloyed steel. Although Cu addition promotes the precipitation of NiAl phases， leading to larger size and higher number of Cu-NiAl composite precipitates in the Cu/Ni alloyed steel compared with the single NiAl precipitates in the Ni alloyed steel， the precipitation strengthening effect of the Cu-NiAl composite precipitates is not significantly higher than that of the single NiAl precipitates. This is because the latter， with its single precipitate sizes below the critical size， strengthen through the dislocation shearing mechanism， whereas the former， with its composite precipitates exceeding the critical size， strengthen via the dislocation Orowan mechanism， resulting in weakened precipitation strengthening. Consequently， the aging precipitation strengthening effect of Cu/Ni steel is not higher than that of the Ni steel.

CuNiIn coatings are prepared on the surface of TC4 titanium alloy using cold spray technology， and the effects of gas types （helium， nitrogen） and preheating temperatures （500， 700 ℃） on the microstructure， microhardness， bonding strength， and gas fretting wear performance of the coatings are investigated. The results show that under the same gas preheating temperature， the porosity of coatings sprayed with helium is lower than that of coatings sprayed with nitrogen， and microhardness， bonding strength， and wear resistance are all superior to those of coatings sprayed with nitrogen. When the gas preheating temperature increases from 500 ℃ to 700 ℃， the porosity of the coatings sprayed with both gases decreases significantly （helium： from 1.4% to 0.05%， nitrogen： from 1.7% to 0.5%）. The hardness of coatings sprayed with helium increases from 213HV to 292HV， while that of coatings sprayed with nitrogen decreases from 275HV to 237HV. The increase in gas preheating temperature has no significant effect on the bonding strength of the coatings， but the type of gas has a significant effect on the bonding strength of the coatings， the average bonding strength of sprayed coatings with helium （70 MPa） is 30 MPa higher than that of sprayed coatings with nitrogen （40 MPa）. The wear rate of coatings sprayed with helium and coatings sprayed with nitrogen decreases with the increase of gas preheating temperature （helium： from 1.8% to 1.41%， nitrogen： from 2.21% to 1.51%）. With the increase of fretting displacement amplitude， the wear form of the coatings under optimized parameters changes from adhesive wear to abrasive wear.

Diamond films prepared by conventional microwave plasma chemical vapor deposition （MPCVD） often face issues such as low growth rates，disordered grain orientations，and non-diamond phase defects，which limit further enhancement of their optical properties. This study introduces CO₂ as an auxiliary gas to deposit high-quality diamond films using the MPCVD method. Diamond film deposition is conducted by introducing different flow rates of CO₂， and the optical emission characteristics of the plasma under varying CO₂ flow rates are measured using optical emission spectroscopy （OES）. The crystallinity quality， grain orientation， surface morphology， and growth rate of the diamond films are characterized by XRD， Raman， and SEM. The results indicate that adding a certain amount of CO₂ （flow ratio of CO₂/CH₄=2/6） is conducive to obtaining diamond films with a high （110） preferred orientation （I₂₂₀/I₁₁₁=18.19）. An excessively high CO₂/CH₄ flow ratio intensifies the etching effect of oxygen-containing groups， reducing the degree of preferential grain orientation. The addition of an appropriate amount of CO₂ significantly improves the crystalline quality of the diamond， with the full width at half maximum （FWHM） of the diamond characteristic peak decreasing from 12.68 cm^-1 to 8.26 cm^-1. Furthermore， the addition of a suitable amount of CO₂ promotes diamond growth to some extent. Under the optimized flow ratio condition of CO₂/CH₄=2/6， this study successfully prepares a high （110） orientation （I₂₂₀/I₁₁₁=18.19） diamond film with a growth rate of 4 μm/h. After polishing， the self-standing diamond film achieves a transmittance of 71% at the 10.6 μm wavelength. Its transmittance in the long-wave infrared band approaches the theoretical value， meeting the requirements for applications such as long-wave infrared optical windows and extreme ultraviolet lithography machine windows.

A solvent-free epoxy modified cyanate ester resin for winding is prepared by modifying bisphenol E cyanate ester/bisphenol A cyanate ester/acetylacetone copper blend with resorcinol diglycidyl ether （RDGE）. The influence of RDGE content on the processability of the resin and the mechanical，thermomechanical，dielectric，and moisture absorption properties of cured resin is investigated. The results show that the viscosity of the resin at is 430 mPa·s @ 25 ℃，which is suitable for solvent-free winding. The processing window lasts for up to one month. RDGE has a catalytic effect on the curing reaction of cyanate esters. The curing temperature of the modified resin is 180 ℃，and the post-treatment temperature is 240 ℃. The oxazolidinone ring generated by the reaction between RDGE and cyanate ester enhances the toughness of the cured resin，while reducing BECy by an equal amount to maintain the processability of the winding process partially offsets the toughening effect. The mechanical properties of the resin cured material reach their maximum at an RDGE content of 20%，with tensile strength and modulus of 78.45 MPa and 3.50 GPa，elongation at break of 2.77%，and bending strength and modulus of 152.49 MPa and 3.48 GPa，respectively. At this point， the moisture resistance of cured resin has improved，with a water absorption rate of 1.60% after 100 h of boiling at 100 ℃.However，the glass transition temperature and dielectric properties have decreased， with a T_g of 247 ℃. The dielectric constant in the frequency range of 7-15 GHz is 3.04-3.05，and the dielectric dissipation factor is 0.013-0.014.

In order to reveal the temperature sensitivity of the impact dynamics of nitrile butadiene rubber（NBR） materials，SHPB impact test experiments under different combinations of conditions are designed by changing the loading strain rate，temperature and other parameters. The results show that： with the increase of temperature and strain rate，the specimen shows the deformation characteristics of “round cake-disc-disc crack” after impact；when the temperature is less than 70 ℃，the difference between the stress-strain curves of specimens with different strain rates is small，and the temperature sensitivity is weak，and higher than 70 ℃，the difference is larger，and the temperature sensitivity is enhanced；under the same strain rate，the yield strength is related to the temperature sensitivity of the specimen. Under the same strain rate，the yield strength is approximately linearly and negatively correlated with temperature，and under different strain rates，the larger the strain rate is，the smaller the slope of the straight line is，i.e.，the more significant the effect of temperature on the yield strength is；when the temperature is greater than 55 ℃，the dynamic modulus is negatively correlated with the temperature and shows strong temperature sensitivity，and the relationship between the two is insignificant when the temperature is less than 55 ℃. The results of the study further enrich the related research on the dynamic properties of NBR，which is of great significance for the selection of NBR materials under the complex temperature environment.