Based on the current status and requirements of wear in zirconia ceramics， in response to the problem friction reduction performance of single-textured specimens， different texture types are combined to extract biomimetic contours from biological surfaces and design various novel composite biomimetic textures. The numerical simulation and the experimental investigation methods are used to analyze the friction reduction performance of composite biomimetic textures，solving the Reynolds equation numerically， studying the influence of composite texture types on oil film load capacity， pressure distribution area， and maximum static pressure， and conducting experimental exploration of the tribological performance using a friction and wear testing machine. The results indicate that composite biomimetic textures exhibit higher oil film load capacity， wider pressure distribution areas， and lower friction coefficients compared to other texture types， among them， the comprehensive anti-friction effect of the scale + feather composite texture is the best； the friction reduction mechanism of composite biomimetic textures can be mainly attributed to changes in contact stress points， the asymmetric distribution of pressure and abrasive storage properties， and the form of pressure distribution of composite texture is highly dependent on a single texture type.

Lead sulfide quantum dots （PbS QDs） have excellent optoelectronic properties and strong near-infrared light absorption，making them ideal materials for the preparation of near-infrared photodetectors. However，there are still challenges in the process and insufficient performance of the PbS QDs-based optoelectronic detection. In this study，PbS QDs are synthesized by the hot injection method，and the PbS quantum junction infrared detector is prepared by the layer-by-layer method and the solid-state ligand exchange method. The photoelectric performance of the PbS quantum junction infrared detector is improved by the thermal annealing process，and the effect of annealing temperature on the photoelectric performance of the PbS quantum junction is described. The results show that annealing effectively reduces the dark current of the PbS quantum junction infrared detector while increasing the photocurrent，and obtains a stable photoresponse current output. After annealing，the response time of the PbS quantum junction infrared detector is shortened，resulting in a time of 1.9 ms and a delay time of 3.2 ms. The sensitivity of the detector is improved，and the responsivity and detectivity are increased by 1.2 times and 1.3 times，respectively，resulting in a responsivity of 0.78 A·W^-1 and a detectivity of \mathrm{7.8}\times {\mathrm{10}}^{\mathrm{11}}\mathrm{c}\mathrm{m}\bullet \mathrm{H}{\mathrm{z}}^{\mathrm{1}/\mathrm{2}}\bullet {\mathrm{W}}^{-\mathrm{1}}. Annealing effectively improves the crystallinity and the carrier mobility of PbS QDs thin films，while reducing the defect states at the film and interface，resulting in a comprehensive improvement in the optoelectronic performance of PbS quantum junction infrared detectors.

With the widespread application of carbon fiber reinforced polymer （CFRP） in the aerospace field， studying the friction performance at the interface of CFRP and aluminum alloy connections has become increasingly important. This study experimentally investigates the influence of surface microtexture parameters on the friction performance at the aluminum alloy-CFRP interface. The results indicate that both contact pressure and microgroove geometric parameters significantly affect the interface friction performance. As the contact pressure increases from 7.5 MPa to 30 MPa， the sliding friction coefficient significantly decreases， primarily due to the formation and enhancement of a self-lubricating film. Under high contact pressure， the microstructures on the aluminum alloy surface embed into the CFRP plate， creating a plowing effect. The micro-cutting action generates epoxy resin debris that fills the microstructure grooves， forming a stable lubricating film. The groove depth has the most significant impact on friction performance， with a groove depth of 31.8 μm significantly reducing the sliding friction coefficient to 0.197. The synergistic effect of contact pressure and microtexture geometric parameters markedly improves the interface friction performance and connection strength. This study provides theoretical basis and practical guidance for optimizing composite material connection technology.

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

The preparation of carbon paper used phenolic resin as matrix carbon， and different heat treatment temperatures （1400-2700 ℃） are used to obtain matrix carbon with different structures. At the same time， the effect of matrix carbon content and structure on carbon paper for proton exchange membrane fuel cell is studied. The results show that the matrix carbon in carbon paper is more prone to graphitization transformation than carbon fiber. As the content of the matrix carbon increases， the d₀₀₂ diffraction peak of the carbon paper becomes sharper. When the heat treatment temperature increases from 2100 ℃ to 2400 ℃， the graphitization of the carbon paper increases by 45.2%， which is the largest increase. With the increase of heat treatment temperature， the carbon papers， with different matrix carbon ratios， show differences in performance trends. When the carbon content of the matrix is 60%（mass fraction， the same below） and 120%， the thickness of the carbon paper gradually decreases with the increase of the graphitization temperature， and the tensile strength of the carbon paper has a slight change； when the carbon content of the matrix is 200% and 350%， with the increase of graphitization temperature， the thickness of carbon paper decreases slightly and then increases， and the tensile strength of carbon paper decreases rapidly. The surface resistivity of carbon paper shows a downward trend with the increase of heat treatment temperature， and its change trend is basically consistent with the change trend of thickness. Therefore， when preparing carbon papers with different properties， it is necessary to consider the synergistic effect of matrix carbon content and structure.

Interlayer crack is a significant obstacle to the wide-scale implementation of light-cured additive manufacturing in industrial applications. The formation mechanism of crack defects during the forming and debinding stages of the process is investigated and their effects on the properties of light-cured ZrO₂ ceramics are analyzed. Furthermore， the study compares and analyzes the influence of exposure time and debinding rate on the distribution of cracks in ZrO₂ ceramics. The research analyzes and compares the influence of exposure time and debinding rate on the distribution of cracks in ZrO₂ ceramics. The results indicate that it is easier to obtain defect-free ceramic green bodies when the slice thickness matches the exposure layer thickness. Moreover， the study observes that the green body exhibits the least number of surface cracks when the debinding rate is set at 0.1 ℃/min. Consequently， the research achieves the successful production of ceramic parts with a density of 99% and a flexural strength of 450 MPa.These findings establish a solid scientific foundation and provide valuable technical guidance for the manufacturing and application of defect-free ZrO₂ ceramics using light-cured additive manufacturing.

8%（mass fraction）Y₂O₃ partially stabilized zirconia （8YSZ） is a currently commonly-used top-coat material for thermal barrier coatings （TBCs） applied to turbine blades in aero-engines. However， its volume change induced by high-temperature phase transitions above 1200 ℃ can easily lead to cracking and failure of TBCs. Sc₂O₃ is employed as an alternative stabilizer to fabricate 8%Sc₂O₃-92%ZrO₂（mole fraction） ceramics （8SSZ） via a solid-state synthesis method. The thermophysical properties of 8SSZ and conventional 8YSZ， including thermal expansion coefficient （CTE）， thermal conductivity， and high-temperature phase/grain stability， are systematically compared. The results show that after heat treatment at 1400 ℃ in a muffle furnace， the CTE of 8SSZ measured by a dilatometer ranges from 8.91×10^-6 K^-1 to 10.7×10^-6 K^-1， which is comparable to that of 8YSZ. Thermal conductivity tests reveal that 8SSZ exhibits a thermal conductivity of 2.59 W/（m·K）， approximately 20% lower than that of 8YSZ. X-ray diffraction （XRD） and scanning electron microscopy （SEM） results demonstrate that 8SSZ maintains phase stability without phase transitions after 500 h at 1400 ℃， outperforming 8YSZ in high-temperature phase stability. However， 8SSZ still exhibits the issue of excessive grain growth.

Microstructures and mechanical properties of GH4169 alloy cylinder and its weld joints in a supercritical water reactor are studied after operating 2000 h. The results show that the GH4169 alloy cylinder exhibits good corrosion resistance under conditions of high temperature， high pressure， and sucrose mixed solution； the thickness loss rate of the cylinder is 0.005-0.255 μm/h； the corrosion products primarily consist of oxides and phosphates. However， the welded joints connecting the cylinder and other components represent a vulnerable point that significantly impacts the remaining lifespan of the reactor. The calculated crack propagation rate of the GH4169 alloy cylinder is 5.25 μm/h， indicating that it would only take 762 h for the crack to penetrate through the wall of the connector. Additionally， severe fracture occurs （the circumferential length of the crack is approximately 1/4 of the circumference） at the weld joint between cylinder and stainless-steel， resulting from the synergistic effects of galvanic corrosion， crevice corrosion， and concentrated stress. Despite these challenges， the strength loss of the cylinder is relatively small， which means that the cylinder maintains satisfactory mechanical properties.

To develop high-temperature wear resistant steel with high tempering stability that can be used in high temperature environments， the bond energy between different alloying elements and C element is calculated by solid and molecular empirical electron theory， and a series of TiC particle-reinforced high-temperature wear-resistant steel components are designed. The precipitation temperature of TiC particles is calculated by Thermo-Calc software and the tempering stability of the steel plate after the best heat treatment is tested at different temperatures and time. The results show that the bond energy formed by Cr， Mo， and W with C is significantly higher than that of Fe—C. Therefore， the activation energy of C atom diffusion in martensite increases， which hinders the diffusion of C atom in martensite and improves the tempering resistance of martensite. Therefore， Cr， Mo， and W are determined as the main addition elements to improve the thermal stability of TiC-reinforced martensitic wear-resistant steel. TiC particles precipitate in the temperature range of 1400-1500 ℃， and the particle morphology shows that the particles distribute like grain boundaries. After thermomechanical processing， micron TiC particles can uniformly distribute on the matrix. The experimental results of tempering stability show that the addition of Cr and W elements greatly improves the tempering stability.

The desirable combination of ultra-high strength and good toughness enables the secondary hardening ultra-high strength steel widely used in aerospace and energy equipment. The influence mechanism of quenching temperatures on the microstructure and mechanical properties of Co-conserving 2.2 GPa ultra-high strength steel is investigated by using scanning electron microscope（SEM），transmission electron microscope（TEM），tensile and impact testing machine. The results show that when the quenching temperature is 950 ℃， there are many undissolved M₆C carbides and unrefined grains in the matrix， resulting in lower strength （tensile strength：2072 MPa， yield strength：1873 MPa）. As the quenching temperature increases， recrystallization promotes the refinement of the matrix grains， and the number of M₆C carbides gradually decreases； such partial dissolution favors the precipitation of hardening phases， resulting in a recovery of strength； when the quenching temperature is 1030 ℃， the experimental steel has excellent combination of strength-plasticity-toughness： the tensile strength is 2251 MPa， the yield strength is 1901 MPa， the elongation is 9%，and the V-notch impact absorbed energy is 9 J. By further increasing the quenching temperature， the rapid growth of austenite grains leads to severe plasticity attenuation， with elongation of only 4.5% at 1120 ℃. Between 1030-1090 ℃， there is a competitive relationship between the dissolution of M₆C carbides and grain growth. Although higher temperature quenching promotes dissolution， the severe coarsening of grains offsets the former’s beneficial effect on toughness to enable a stable performance of strength and toughness.