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.

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.

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.

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.

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.

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.

This study utilizes mushroom stalks as a biological template and melamine as a precursor for carbon nitride to synthesize g-C₃N₄/C，via thermal polymerization method. Copper sulfate pentahydrate （CuSO₄·5H₂O），ammonium molybdate tetrahydrate （（NH₄）₆Mo₇O₂₄·4H₂O），and thiourea （CH₄N₂S） are selected as the sources for Cu，Mo，and S，respectively. A two-step hydrothermal process is employed to prepare CuS/MoS₂ composites with different mass ratios. Then CuS/MoS₂ is anchored on the surface of g-C₃N₄/C to obtain CuS/MoS₂-g-C₃N₄/C composite electrode materials. The composite electrode materials are characterized by their phase structure，microstructure，pore structure，and capacitance performance. The results indicate that the CuS/MoS₂-g-C₃N₄/C composite electrode materials exhibit high purity，good crystallinity，good phase contact interface， and abundant porous structure. In electrochemical performance testing，the CuS/MoS₂ composite material with a mass ratio of MoS₂ to CuS at 1∶2 demonstrates optimal electrochemical performance，achieving a specific capacitance of 230 F·g^-1 at a current density of 1 A·g^-1. When the mass ratio of CuS/MoS₂ to g-C₃N₄/C is 1∶1，the CuS/MoS₂-g-C₃N₄/C composite material exhibits the best electrochemical performance，with a specific capacitance of 434.7 F·g^-1. Moreover，after 1000 cycles，the capacitance retention rate is 89.2%，showing good stability.

The β titanium alloy Ti-1300 is fabricated utilizing laser engineered net shaping （LENS） technology. This study systematically examine the microstructural evolution of the alloy along the deposition direction during the LENS process， and elucidate the intrinsic relationship between its mechanical properties and microstructure. The results indicate that the thermal cycling of each deposited layer in the LENS process has a profound impact on the microstructural evolution. Initially， columnar crystals are formed with a thickness of （15.6±1.2） mm， comprising approximately 20% of the total deposited thickness. Subsequently， these grains transform into equiaxed grains. Within the as-deposited grains， the microstructure undergo a transition from a basket-weave structure to a lamellar structure， and the discontinuous grain boundary α phase changes to a continuous grain boundary α phase along the deposition direction. Notably， the basket-weave microstructure imparts exceptional strength to the alloy. However， the continuous grain boundary α phase tends to promote intergranular fracture， resulting in reduced ductility.

Welding of cryogenic 9Ni steel is performed using NiCrMo alloy systems with different Nb and C contents. The microstructure and mechanical properties of the welded joints are investigated， and the fracture toughness of the joints under ultra-cryogenic conditions is analyzed by crack tip opening displacement （CTOD） tests. The results show that the welded joint exhibits distinct zoning characteristics. The nickel-based weld metal primarily consists of an austenitic columnar crystal matrix and secondary phases. The secondary phases include fine nanoscale banded precipitates and Nb-rich solidification phases formed in the final stage of weld pool solidification. The precipitates are mainly composed of metal carbides （MC） and Laves phases. With the increase of Nb and C content， the number and average particle size of secondary phases in the nickel-based alloy increase， leading to an improved tensile strength of the joint， but reduced cryogenic impact toughness and fracture toughness. The load-notch opening displacement （F-V） curves show that the characteristic load F_m of the joint first increases and then decreases with the addition of Nb and C， while the corresponding characteristic plastic displacement value V_p decreases monotonically with the increase of secondary phases. The fracture surface of the CTOD specimens shows the same zoning characteristics. As the Nb and C content increases， the width of the stable crack propagation region on the fracture surface gradually decreases， indicating a deterioration in the fracture toughness of the weld.