Continuous fiber reinforced and toughened ceramic matrix composites (CMCs) are key thermal structural materials in aerospace and other fields. Mechanical connectivity, as one of the most reliable connectivity methods, is an essential method to achieve connectivity of large and complex CMCs components. At present, research on CMCs joints is rapidly developing, but there is few comprehensive review literature on CMCs joints. Based on the research work in the field of CMCs joints in recent years, the preparation and mechanical property characterization methods of CMCs fasteners were summarized in this paper, the damage and failure mechanism of CMCs fasteners were systematically stored and discussed, and focusing on the influencing factors and laws of mechanical properties of CMCs fasteners from the perspective of material properties and external environment. The research work on CMCs mechanical joints was presented, and the damage law, failure mechanism, finite element simulation and reliability of CMCs connectors were prospected.

Nickel-based superalloys have attracted significant attention due to their outstanding high-temperature strength, corrosion resistance, and oxidation resistance, and are widely used in aerospace and other fields. This article provides a comprehensive review of the preparation methods, common grades, and microstructure and properties of additive manufactured nickel-based superalloys, summarizes the current issues, and proposes future areas for exploration. Nickel-based superalloys prepared by metal additive manufacturing technology have excellent performance, can achieve precise forming of complex components, and have minimal material waste during the manufacturing process. They are expected to become an important production process for nickel-based superalloys components in fields such as aerospace. Common methods for additive manufacturing of nickel-based superalloys include laser powder bed melting, directed energy deposition, and arc additive manufacturing. Powder bed melting is widely used for manufacturing high-precision and complex parts, but it has a relatively slow manufacturing speed and higher equipment and material costs. Directed energy deposition has higher degrees of freedom and flexibility and can be used to prepare functional gradient materials, but it has lower accuracy. Arc additive manufacturing has lower equipment and material costs and is suitable for rapid manufacturing of large parts, but the surface roughness of the alloy produced by this method is poor and requires additional processing or post-treatment. Nickel-based superalloys widely studied in the additive manufacturing process include IN625, Hastelloy X, and other solid solution strengthened alloys, as well as IN718, CM247LC, IN738LC, and other precipitation strengthened superalloys. Compared with traditional casting and forging methods, the unique layer-by-layer forming and rapid cooling and heating process of additive manufacturing result in a coarse columnar grain structure and a unique microstructure with a large number of fine grains. It also forms unique melt pool structures and dislocation cell structures. However, the alloys obtained by additive manufacturing generally require heat treatment to control grain structure and precipitated phases, which affects the mechanical properties of the alloy. In addition, the mechanical properties of additive manufactured nickel-based superalloys are also related to specific preparation methods and alloy types. Although additive manufacturing has been widely used in the preparation of nickel-based superalloys, there are still issues such as anisotropy in microstructure and properties, high sensitivity to alloy cracking, and a lack of corresponding specifications and standards. In the future, further exploration is needed in areas such as heat treatment, customization and development of specialized alloys, investigation of the process-structure-function relationship, and computational modeling.

The pollution of heavy metal ions in wastewater has caused serious harm to human health, and the adsorption method has attracted much attention because of its high efficiency, economy, simplicity, and good selectivity. SiO₂ aerogel is a potential adsorbent for removal of heavy metal ions in wastewater due to its high specific surface area (>500 m²/g), high porosity (>80%), controllable surface group and good physical/chemical stability. Herein, the preparation methods of SiO₂ aerogel and its effect on microstructure were briefly introduced, focusing on the functionalization methods of SiO₂ aerogel and the adsorption performance and factors of functionalized SiO₂ aerogel for the adsorption of heavy metal ions in wastewater, and the adsorption mechanism and adsorption kinetics process of functionalized SiO₂ aerogel as heavy metal ions adsorbent were analyzed. It was pointed out that the controllable preparation with low cost and short process, effective functionalization and efficient adsorption of various heavy metal ions are the future development directions of SiO₂ aerogels as absorbent.

Stress corrosion cracking (SCC), as an important research direction in the interdisciplinary of material mechanics and corrosion electrochemistry, is one of the main failure modes of stainless steel components. Compared with traditional wrought technology, additive manufacturing (AM) 316L stainless steel has complicated microstructure and inherent defects including pores and lack of fusion places (LOF) caused by additive manufacturing process, resulting in more complex SCC behavior. Herein, the basic SCC behavior of 316L stainless steel was discussed in detail on the basis of the researches of AM316L stainless steel at home and abroad. The main contents include two stress corrosion mechanisms of hydrogen induced cracking and anodic dissolution. Two behavior of transgranular cracking and intergranular cracking were described. The effects of microstructure on SCC behavior of AM316L, including twins, different crystal interface, pores, LOF, and element segregation were summarized. The current situation and advantages of three in-situ characterization methods, including electrochemical noise, high-resolution neutron diffraction and three-dimensional morphology characterization were introduced, which are of great significance to explore the SCC behavior of AM316L. Finally, the prospective future of the research directions of SCC behavior of additive manufacturing stainless steel were proposed, including the research of SCC characteristics under high temperature irradiation environment and the principle of stress distribution and restructuration at crack tips.

MXenes are a new type of two-dimensional layered transition metal carbides and nitrides prepared by selective etching of MAX phase materials. Due to their excellent physical, electronic and chemical properties, MXenes have been widely used in electromagnetic shielding, biomedicine, energy storage, sensors, water purification and other fields. At the same time, MXenes and their composites can effectively improve the catalytic efficiency of noble metal catalysts or directly serve as a class of non-precious metal catalysts due to their large specific surface area, excellent electrical conductivity and stability, and are regarded as a promising class of fuel cells electrocatalysts or supports. The structure, properties and preparation methods of MXenes were introduced in this paper, and the latest application research results of MXenes and their composites in the fields of oxygen reduction, formic acid oxidation, methanol oxidation and ethanol oxidation reactions were overviewed, and the main problems existing in MXenes materials were pointed out (for example, it is difficult to preparing uniformly dispersed multi-layer MXenes flakes or few or even single-layer MXenes flakes, which are easy to re-stack due to higher surface energy, etc.), preparing more new MXenes and composite them with various materials were put forward, in order to promote the application of MXenes and their composites in the field of fuel cells.

High entropy alloys have been proposed in 2004, which are expected to be widely used in aerospace, petrochemical and other fields due to their excellent properties compared with the traditional alloys, and have become a hot spot in current metal material research. It has become one of the methods to improve the comprehensive properties of high entropy alloys by introducing suitable reinforcement phase into the high entropy alloy matrix, and to form high entropy alloy matrix composites (HEAMCs). In this review, according to the current research status in HEAMCs at home and abroad in the past few years, the reinforcement phase selection, preparation method, phase structure, microstructure and strengthening mechanism of HEAMCs were systematically introduced, and the evolution of properties of HEAMCs were summarized, including strength and plasticity, hardness, wear resistance and corrosion resistance. Finally, the challenges to HEAMCs were discussed and future research directions in HEAMCs were suggested.The wettability between the reinforcement phase and the matrix seriously affects the preparation and performance of large-scale composites, and finding an efficient and simple method to prepare large-scale composites is a problem that needs to be solved in high-entropy alloy matrix composites; reinforcing particles will lead to a decrease in plasticity, and the balance between strength and plasticity of metal matrix composites also needs to be studied.

Hydrogel is a cross-linked three-dimensional network hydrophilic polymer material, which can absorb and retain a large amount of water and maintain a certain shape. In recent years, with the depletion of petroleum resources and the increasing attention of human beings to environmental issues, natural or modified polymer synthetic polymer hydrogels have become a research hotspot. Cellulose and its derivatives are a large class of renewable natural polymer materials, which have the characteristics of rich resources, wide variety, non-toxic and renewable, etc. The synthesized cellulose-based hydrogel has good water absorption, water retention, biocompatibility and biodegradability, etc., which can be used in medical, environment, agriculture and other fields. The research progress of the construction and application of cellulose-based hydrogels in recent years was reviewed in this paper. The microscopic network structure is combined with the macroscopic properties of the hydrogel. The mechanical properties, swelling properties and adsorption properties of the single network, interpenetrating network and semi-interpenetrating network cellulose-based hydrogels were summarized, and their applications in medical, environmental, agricultural and electronic fields were introduced. The development of cellulose-based hydrogels with both mechanical properties and biocompatibility, and the development of more green economic methods for the synthesis of cellulose-based hydrogels for industrial applications were proposed.

The development of nuclear reactor structural materials with excellent comprehensive performance is the basis of nuclear energy development, and it is one of the difficulties that have long restricted the promotion of nuclear energy. Multiprincipal element alloys(MEAs) have been recognized as candidate materials for advanced reactor structural materials due to their good irradiation resistance and mechanical properties, which has expanded a broad space for the design of new radiation-resistant materials. In recent years, the research on the irradiation damage of multiprincipal element alloys has tried to reveal the influence of some factors and characteristics of multiprincipal element alloys on the formation and evolution of defects in the irradiation process. For example, the type, number and concentration of alloying elements, lattice distortion, chemical short range order, etc. Although some existing research results show that the above factors can improve the resistance of multiprincipal element alloys to irradiation damage, under different irradiation conditions, the influence mechanism of the above factors on the formation and evolution of defects in multiprincipal element alloys is quite different, and it is difficult to draw generalization conclusions. Focusing on the four aspects of irradiation swelling, helium bubble formation, irradiation-induced element segregation and phase transition, irradiation hardening of FCC and BCC systems.The research progress of multiprincipal element alloys in irradiation damage in recent years was reviewed, the mechanism of action of multiprincipal element alloys to improve radiation resistance was summarized.And based on this, the future research directions for multiprincipal element alloys used in nuclear power structures were prospected, including tuning short-range order, high-entropy ceramics, additive manufacturing technology, accelerating development of new materials by integrating high-throughput computing with machine learning, etc. Finally, it is pointed out that new radiation-resistance MEAs must be designed based on the actual environment of material service from the perspective of composition design.

As one kind of advanced high temperature structural and functional materials, it is necessary for fiber reinforced silicon carbide matrix composites (SiC CMCs) in the field of thermal management (TM) to combine the efficient heat transfer and high temperature heat resistance. Common fibers reinforced SiC CMCs, such as carbon fibers reinforced SiC CMCs (C_f/SiC or C_f/C-SiC), silicon carbide based fiber reinforced SiC CMCs (SiC_f/SiC), etc., have a low degree of graphitization of the reinforcing fiber and are difficult to form an effective heat transport network. The latest research progress on the preparation and properties of fiber reinforced SiC CMCs with highly thermal conductivity was reviewed in this paper. The heat transport ability of fiber reinforced SiC CMCs can be improved by introducing highly thermal conductive phase, optimizing interfacial structure, making silicon carbide crystal coarse-grained, and designing preform structure. Moreover, the development of the fiber reinforced SiC CMCs with highly thermal conductivities was prospected, that is, comprehensively considering the factors that affect the performance of SiC CMCs, flexibly using the structure-activity relationship between the microstructure and properties of the composites, in order to prepare fiber reinforced SiC CMCs with stable size, excellent properties.

Proton exchange membrane fuel cell (PEMFC) usually need an activation process to obtain its best electrochemical performance.Compared with the traditional activation methods, electrochemical hydrogen pump has the advantages of saving time and hydrogen cost. The electrochemical hydrogen pump is a method in which hydrogen is oxidized into protons at the anode, and the protons migrate to the cathode with an applied electric field, and then are reduced to hydrogen again. The performance, internal impedance and electrochemical specific area(ECSA) changes of PEMFC after electrochemical hydrogen pump activation were studied with the help of polarization curves, electrochemical impedance spectroscopy(EIS) and cyclic voltammetry(CV) tests. Then the mechanism of the hydrogen pump activation was analyzed. Moreover, the influence of different current densities, inlet humidities and activation temperatures were investigated. The results show that after the hydrogen pump activation, the fuel cell performance is improved obviously, the slope of Tafel curve is decreased, the charge transfer resistance and mass transfer resistance get lower values, while the ohmic resistance is basically unchanged, and the ECSA is increased. Therefore, the mechanism of the hydrogen pump activation is related to the quantity of active species and microstructure of catalyst layer. The performance of hydrogen pump activation under 200 mA·cm^-2 is better than that of under 100 mA·cm^-2. The performance of hydrogen pump activation under the inlet humidity of 150%RH is better than that of 100%RH and 200%RH. In addition, the activation temperature has little impact on the PEMFC performance after hydrogen pump activation, and the fuel cell can be fully activated by hydrogen pump activation for 30 min at room temperature.

Owing to the feature of ultrahigh power density, the dielectric capacitors play an increasingly important role in the field of industrial production, basic scientific research, aerospace, and military industry in recent years. However, the relatively low energy storage density of the dielectric capacitors generally leads to their big sizes, which is difficult to meet the miniaturization requirements of future devices. Polymer-ceramic nanocomposites can combine high permittivity of the ceramic fillers and the excellent breakdown strength of the polymer matrix, thus achieving excellent energy storage performance. At present, developing the polymer-ceramic nanocomposites with high energy storage density is the key to realize the miniaturization goal of dielectric capacitors in the future. The current research progress of polymer-ceramic nanocomposites for energy storage capacitor applications from three perspectives was systematically summarized, including regulation of the nanofillers, optimization of the interfaces, and design of the multilayer composite structure. Notably, the influences of the dimension, size, species, hierarchical structure of the nanofillers, interface optimization methods such as surface modification and core-shell structure construction, as well as multilayer structure design such as sandwich structure and gradient structure on the permittivity, breakdown strength and the energy storage density of the nanocomposites were introduced in detail. Meanwhile, the structure-activity relationships between the microstructure of nanocomposites and their energy storage properties were further analyzed and discussed. Finally, based on the challenges and shortcomings of the current research, the important development directions of this field in the future were proposed, including selecting the new 2D nanofillers, enhancing the energy storage efficiency, employing multimode combined optimization strategy, and constructing the corresponding dielectric capacitors.

Microneedles (MN) as a minimally invasive device consisting of a micro-raised array, can penetrate the cuticle to the epidermis and dermis, and which has the advantages of safety, painless, minimally invasive, self-administration and convenience. As a new kind of microneedles, hydrogel microneedles have attracted more attentions in the medical field due to its excellent performance. Hydrogel microneedles have good biocompatibility and mechanical properties, and can be completely removed after skin action without residual polymer in the body. Its unique swelling property can realize minimally invasive extraction of human detection substance and slow release of drugs, which can play a huge role in the field of personal health monitoring and drug controlled release in the future. The mechanism of action, design, preparation and application of hydrogel microneedles were reviewed in this paper, focusing on the current design parameters of hydrogel microneedles and their applications in drug delivery, extraction monitoring and wound healing, and the problems of hydrogel microneedles in skin infection risk, pharmacokinetics and wearing comfort were pointed out. In the future, the key research direction is to combine with intelligent devices to realize both human body monitoring and intelligent drug controlled release on the microneedle patch.

Based on the self-made Zr_0.5Hf_0.5C precursor and commercial liquid polycarbosilane, C/Zr_0.5Hf_0.5C-SiC composite was successfully prepared by the precursor impregnation and pyrolysis(PIP) process. The influence of the thickness of pyrolytic C coating on the structure and bending properties of composite materials was studied. The results show that the self-made Zr_0.5Hf_0.5C precursor can be converted into Zr_0.5Hf_0.5C solid solution at a relatively low temperature of 1400 ℃. Because of its good permeability, the transformed Zr_0.5Hf_0.5C matrix exists in both the inter-bundle and intra-bundle regions of the C/Zr_0.5Hf_0.5C-SiC composite, which presents as a layered structure on SiC matrix. The phase composition of C/Zr_0.5Hf_0.5C-SiC composite mainly includes C, SiC and Zr_0.5Hf_0.5C. The densities of three groups of composites with different thicknesses of pyrolytic C coating (0.67, 0.84, 1.36 μm) are 2.07, 1.99, 1.98 g/cm³, respectively. SiC content in the composite decreases with the increase of the thickness of pyrolytic C coating. The three groups of composites with different thicknesses show pseudoplastic fracture mode during bending loading tests, bending strength, bending modulus and fracture toughness are above 410 MPa, 60 GPa and 15.6 MPa·m^1/2, respectively. Good interface bonding and pre-introduced SiC matrix are the keys to obtaining excellent bending properties of C/Zr_0.5Hf_0.5C-SiC composites.

Lithium-ion capacitors are energy storage devices between lithium-ion batteries and supercapacitors, which have both high energy density and high power density, and are considered as one of the most promising energy storage systems. In this paper, the research progress of carbon-based and lithium-embedded cathode materials in recent years was summarized, and the classification and modification methods of carbon-based and lithium-embedded electrode materials were introduced in detail. In order to further improve the performance of lithium-ion capacitors, researchers further optimized the cathode materials by means of microstructure regulation, surface modification, doping modification and composite materials, and carried out cathode and anode dynamic matching to comprehensively improve the electrochemical performance of lithium-ion capacitors. Finally, the research hotspots and development directions of cathode materials for lithium-ion capacitors in the future were reviewed in order to provide good electrochemical properties for the next generation of cathode materials for commercial applications.

Advanced polymeric composites (APC) are important structural materials for realizing the lightweight of aerospace vehicles. However, unfavorable factors such as low manufacturing efficiency, high cost, and serious energy consumption hinder the further expansion of APC applications. Resistance implant welding (RIW) technology has the advantages of simple equipment, high welding efficiency, energy saving and environmental protection, and is suitable for the connection of large structural parts with curved surface. It can replace the traditional bonding process and promote APC structural parts to realize green manufacturing, re-manufacturing and recycling. The research progress of APC resistance implant welding process and its application technology were presented in this paper. The challenges faced by APC resistance implant welding technology were introduced. The research status of thermoplastic composite RIW, process parameter optimization for welding pressure and welding time, implant types, thermosetting composite RIW and the application technology of RIW in the manufacturing of large APC structural parts were summarized systematically. The existing problems of APC resistance implant welding were pointed out, which relate to material design, process optimization and fixture manufacturing. In the future, the research on RIW technology of TPC structure is expected to focus on the development of higher strength welding binder, the design of HE with new structure and the improvement of interface bonding strength between binder and HE to improve the bearing capacity of joints. The research on mechanical constitutive model, fatigue strength and service life of RIW joints will be strengthened; the research on welding equipment and fixtures for specific APC components will be carried out to promote RIW engineering to fill the gaps in this area in China.

In order to develop lithium-ion batteries with high energy density, prelithium technology has attracted extensive attention. Li₅FeO₄was successfully prepared by molten salt method with LiNO₃-LiOH mixed lithium salt as reaction medium and lithium source, and nano Fe₂O₃ as iron source in this work. Li₅FeO₄ as cathode prelithiation additive is applied to lithium-ion batteries. The synthesis conditions of Li₅FeO₄ were optimized by orthogonal experiment, and the effect of synthesis conditions on the electrochemical properties of the material was discussed. Li₅FeO₄ was added to the surface of LiFePO₄ positive electrode and assembled with graphite negative electrode to form a full cell. Its effect on the electrochemical performance of the full cells and the mechanism of reducing the initial capacity loss of lithium-ion batteries were studied. The results show that Li₅FeO₄ cathode prelithiation additives with high purity, small particle size and outstanding electrochemical performance can be prepared by molten salt method. When Li₅FeO₄ with a mass fraction of 2.8%(based on the percentage of active materials mass) was added, the discharge specific capacity of first cycle for the LiFePO₄/graphite full cell was 150 mAh·g^-1 at 0.05 C, which was 8.5% higher than that without adding, after 100 cycles at 0.2 C. the capacity still increased by 7.1%, and the irreversible capacity of the svstem was restored.

In order to meet the needs of large area thermal protection(≥1500 ℃)for high-speed aircraft, the high temperature resistant alumina fiber reinforced aerogel composite was used as the thermal insulation layer, and the carbon fiber fabric was used as the panel layer preform. Through the normal needle puncture process and the precursor impregnation pyrolysis process, the integrated TPS material for thermal protection was prepared, and the high temperature resistance performance tests were carried out to provide theoretical and technical support for the engineering application of materials. The results show that the integrated TPS material with good integrity and no obvious defects can be prepared by needle puncture suture technology and PIP process, and the density is only 0.6 g/cm³. When C/SiC composites are used in high-temperature oxidation environment, the oxidizing atmosphere diffuses into the material through defects such as pores and cracks, and oxidizes with carbon fibers, resulting in the degradation of composite properties. The material has excellent high temperature resistance, with mass ablation rate of 0.051 g/s and linear ablation rate of 0.077 mm/s; There is no obvious gap structure, and there is no obvious shrinkage on the whole, showing good high temperature resistance.

Ga₂O₃ is an ultra-wide band semiconductor corresponding to the deep ultraviolet(UV) spectrum, which can be used to prepare solar-blind UV detectors. The solar-blind ultraviolet detectors are widely used in military and aerospace fields dueto strong anti-interference ability, high detection sensitivity and low background noise.The basic properties of Ga₂O₃ materials, including different crystal structures and their preparation, and the recent progress in solar-blind UV detectors based on Ga₂O₃ were introduced in this paper. Among them, metal-semiconductor-metal (MSM) structure of Ga₂O₃ devices are the most common, which are expected to achieve business application with commercial parameters. The Ga₂O₃-based heterostructure and Schottky detectors also exhibit excellent performance and self-supply characteristics. In addition, Ga₂O₃ devices based on thin film transistor become a potential solar-blind ultraviolet detector. They combine the working mechanism of MSM and transistor structure to obtain high light gain, which are suitable for weak signal detection.

Continuous SiC fibers reinforced SiC ceramic matrix composites have wide applications in the aerospace and nuclear fields owing to their excellent high-temperature resistance, good oxidation resistance and mechanical properties. The precursor-derived method has been the most important method for preparing continuous SiC fibers. The introduction of specific hetero elements could effectively improve properties of SiC fibers. Based on the research work on precursor-derived SiC fibers of high performance carried out by our group in the past forty years, this review firstly summarizes the addition methods of hetero elements, mainly including physical blending or chemical modification methods; The role and mechanism of hetero elements have been elucidated from several aspects: increasing the ceramic yield of the precursor, facilitating densification during sintering of the precursor-derived SiC fibers, improving high-temperature resistance of the final SiC fibers, and generating functions of SiC fibers; The composition, microstructure, properties, and developmental status of SiC fibers containing hetero elements, such as Ti, Al, Zr, Fe, B, as well as refractory metals (Hf, Ta, Nb), have been introduced. Furthermore, future research in the development of precursor systems, quantitative study of the relationship between the types and contents of hetero elements and properties of derived fibers, as well as engineering applications of the precursor-derived SiC fibers, has been prospected.

The effect of secondary γ' phase evolution on the creep properties of single crystal superalloy DD6 was investigated at 760℃/785 MPa and 980℃/250 MPa by FESEM and TEM. The results indicate that the secondary γ' phases in DD6 alloy with standard heat treatment are precipitated in the matrix channel after exposure at 1120℃/4 h/AC. Since the secondary γ' phases in the matrix prevent the a/2〈011〉 dislocation gliding in the matrix channel and promote the {111}〈112〉 slip operated in the primary γ' phases at the beginning of creep at 760℃/785 MPa, the secondary γ' phases in the matrix channel decrease the incubation period and significantly improve the primary strain and creep rate. The secondary γ' phases in the matrix will dissolve rapidly at the beginning of creep at 980℃/250 MPa, therefore, the secondary γ' phases have no influence on the creep behaviour of 980℃/250 MPa.

SiC fiber-bonded ceramics (FBCs), as a new thermal-structural material obtained by hot-pressing sintering of SiC fiber, has low porosity, high fiber volume fraction, high temperature resistance, oxidation resistance and high strength. It is an excellent candidate material for high temperature components such as turbine blades and rotors of aero-engine. The research progresses of FBCs were systematically reviewed in this paper. The structural characteristics and preparation methods of two types of FBCs (Tyranohex and SA Tyranohex) were introduced, the relationships among the composition, structure and performance of FBCs were discussed. It was noted that the interface carbon layer plays a crucial role in the performance of FBCs. The mechanical properties of SA-Tyranohex at room temperature and high temperature were highlighted, and the reasons for its excellent high temperature performance were analysed. The examination, verification and application development were summarized. The difficulties of FBCs in forming complex components were pointed out, and the future development trends and research directions were prospected. Finally, it was proposed that conducting research on SiC fiber-bonded ceramics is of great significance for the development of new materials for high-temperature resistant components in China.

As a new material system, the high entropy ceramics have become a hot research topic in the field of materials because of their unique and adjustable properties benefited by the huge component space, unique microstructure and large configuration entropy. The research of the high entropy ceramics is still in the initial stage at present, especially for the accurate composition design theory, preparation of high purity and high conversion powder, new sintering process and other aspects, which need to be further explored. Therefore, the five high entropy effects, new design theory, powder preparation methods, new sintering methods, comprehensive properties and practical applications of high entropy compounds ceramics were sorted and summarized, the composition design of high entropy ceramics (HEC) by the cluster-plus-glue-atom model (CPGA) was analyzed, and the relationship between the components, microstructure, and performance of HEC was explored deeply. The key development direction of future HEC will still be basic theoretical design, especially for the composition and structure of non oxide HEC. At the same time, the breakthroughs in interdisciplinary fields was sought, such as using artificial intelligence machine learning and 3D printing for sample preparation. Finally, the practical applications in structures, thermal barrier and corrosion resistant coatings, machinery, engineering optics, and magnetism were searched, and the strengthening and failure mechanisms were explored and analyzed in-depth under the investigated working environment.

SiC fiber is one of the common reinforcements for ceramic matrix composite (CMC) due to its superior characteristics such as low density, high tensile strength, excellent high temperature resistance and oxidation resistance. The preparation of coating on the surface of SiC fiber can not only improve the mechanical properties, high temperature resistance, oxidation resistance and electromagnetic functional properties of the fiber itself, but also effectively improve the bonding properties of the interface between the fiber and the matrix to promote the fracture toughness and mechanical properties of the composite. The preparation methods of surface coatings on SiC fiber were firstly reviewed in this paper by elaborating on the basic processes and related research progress of etching, deposition, chemical vapor infiltration, and precursor derived methods, and the advantages and disadvantages of different preparation methods were compared. Then the effects of coatings on SiC fibers and their reinforced composite materials were reviewed. Finally, the development trend of surface coating on SiC fibers was briefly summarized. The combination of experimental research and computational simulation can be used to simulate the real service environment of SiC fibers coatings, and the performance of fibers under extreme service conditions can be improved by preparing thermal barrier composite coatings.

Reversible metal electrodeposition device (RMED) is a new type of electrochromic device, which has excellent spectrum regulation ability in visible and infrared regions, and has unique advantages such as simple structure, low energy consumption, multi-color state regulation. It shows great application potential in intelligent window, thermal management, information display and other fields. In recent years, the performance of RMED has been improved through structural design and electrolyte composition optimization, but there are still some problems such as poor open circuit stability, short cycle life and limited size, which seriously hinder the development and application of RMED. From the perspectives of spectral tuning range and performance optimization, the research progress of spectrum regulation devices based on reversible metal electrodeposition was summarized in this article. The spectral tuning range mainly includes visible and infrared bands. The current development status of RMED in the visible light region using different metal deposition systems was briefly introduced, which is also the most widely studied direction at present. The electrode innovation for achieving infrared spectral tuning was the focus of the discussion. The research methods for improving device performance such as open-circuit stability and cycling stability were discussed. Finally, it was pointed out that RMED still faces some development difficulties, and in the future, in-depth and systematic research can be carried out on device performance and theoretical mechanism, among other aspects.

Thermal barrier coating (TBC) materials are an important method to provide thermal protection and prolong service life for aero-engines and gas turbines. In recent years, various kinds of high-entropy (HE) rare earth oxides have emerged in the exploration of novel thermal barrier coating materials, in order to obtain thermal, mechanical, high temperature phase stability, sintering corrosion resistance and other properties better than single principal rare earth oxides through HE effect on the thermodynamics and kinetics of hysteresis diffusion effect, the structure of the lattice distortion effect and "cocktail" effect on the performance. The thermal, mechanical and other performances of HE rare-earth zirconates, cerates, hafnates, phosphates, tantalates, niobates, etc. were summarized and analyzed in comparison with the performance of the corresponding single phases to investigate the various factors affecting the performance. Finally, it was pointed out that in the future, it may be possible to combine experiments with first-principles calculations to select high-entropy ceramic thermal barrier coating materials with superior comprehensive performance; at the same time, extending high-entropy to complex components or medium-entropy ceramic thermal barrier coating materials is also an important development direction.

Two-dimensional covalent organic frameworks (2D COFs) are ideal heterogeneous catalysts, and have been widely used in photocatalysis and electrocatalysis, owing to their high specific surface area, tunable porosity, facile functionalization, highly accessible and dispersed catalytic active sites. Starting from the rational design strategy of the structure and functionalization of COFs, synthetic methods for 2D COFs were reviewed, including solvothermal synthesis, mechanochemical synthesis, microwave synthesis, ionothermal synthesis, sonochemical synthesis, interfacial synthesis, and room temperature synthesis. Furthermore, recent progress of 2D COFs applications in photocatalysis and electrocatalysis was summarized, including hydrogen evolution reaction, oxygen evolution reaction, oxygen reduction reaction, carbon dioxide reduction reaction, and photo/electrocatalytic organic conversion. Finally, the challenges of 2D COFs in photocatalysis and electrocatalysis were summarized, including high cost of organic ligands, difficulty of industrialization, the use of sacrificial agents, and a cooperative coupling reaction strategy was proposed based on photo/electroorganic synthesis and hydrogen evolution or oxygen evolution reactions.

The preparation, purification and application of fullerene were reviewed. The advantages and disadvantages of the preparation and purification methods of fullerene were compared by analyzing the factors such as yield and cost. The application status of fullerene materials in lubrication, catalysis, biomedicine and other fields were summarized. It was also pointed out that the preparation and purification methods of fullerene should be further optimized and improved in the direction of low cost and high yield. At the same time, it was supposed to strengthen the theoretical research on the reaction mechanism of fullerene application in order to develop fullerene materials from the perspective of design.

Titanium carbide (Ti₃C₂T_x) as one of MXene materials, has unique structure, excellent conductivity, stability and superior electrochemical properties. It is often used as electrode material for supercapacitors. Based on the characteristics of the layered structure of Ti₃C₂T_x materials, the research progress in Ti₃C₂T_x based composite materials used for supercapacitor electrode was reviewed, and the structure, properties, preparation and electrochemical performance of Ti₃C₂T_x materials compounded with various types of materials through different technical means were emphatically described. The reasons for improving the properties of Ti₃C₂T_x matrix composites were summarized, including increasing the layer spacing, providing more active sites, and improving the toughness. Finally, the future research priorities of Ti₃C₂T_x matrix composites were pointed out, such as exploring new matrix parent phases, enriching etching methods, improving existing composites, and exploring more and more efficient composites.

The development of energy storage devices that can withstand large and complex deformation is crucial for emerging wearable electronic devices. At present, hydrogels made of conductive polymers have achieved the fusion of high conductivity and versatility during processing. A simple two-step copolymerization method was used to successfully construct a hydrogel supercapacitor with a rich microporous structure: polyvinyl alcohol(PVA) and polyacrylamide(PAM) form a double cross-linked network hydrogel, which endows rigid polymer aniline with flexibility. In addition, polyacrylamide improves the mechanical strength of polyaniline-based hydrogels, making polyaniline-based(NPP)hydrogels have good mechanical and electrochemical properties, and the tensile strength and specific capacitance are 0.3 MPa and 269.12 F·g^-1 under 1 A·g^-1, respectively. The addition of polyaniline(PANI) reduces the internal resistance of polyvinyl alcohol and polyacrylamide double cross-linked network hydrogel(PP) electrode, and its modified resistance value is 39.184 Ω, which makes the NPP hydrogel realize higher electron transmission capacity. The flexible development and integration of such hydrogels provide an alternative strategy of energy systems for diverse applications such as supercapacitors.

Polymer ionic gel is a new type of gel system composed of ionic liquid (IL) and polymer matrix, which has excellent extensibility, high conductivity and good stability. It has broad application space in the field of flexible electronic products, and has attracted the attention of researchers at home and abroad. Based on the investigation of the research progress in related fields in recent years, the matrix classification of polymer ionic gel materials was summarized, the modification methods of conductive hydrogels were discussed, the application of ionic gel in related fields was expounded, and on this basis, the challenges faced by polymer ionic gel and its future development direction were summarized and prospected. It was pointed out that the development of ionic gel with excellent mechanical properties, high conductivity and degradability is the focus of future research. At the same time, improving the environmental stability of ionic gel and reducing the preparation cost of ionic gel are urgent problems to be solved in practical applications. The preparation and application of ionic gel will promote the rapid development of flexible electronic materials.

Implant infection is one of the most common and serious complications in orthopedics, and it is also an important reason for the failure of implant surgery. When bacteria form a biofilm on the implant surface, it is extremely difficult to be eliminated and attracts more bacteria and fungi. A large number of studies have shown that the use of surface modification technology can effectively reduce the adhesion and accumulation of pathogenic bacteria, thereby preventing peri-implant infection. The formation process of bacterial biofilm on the surface of orthopedic implants and the antibacterial mechanism of metal antibacterial agents were first analyzed. Then, some of the most widely used metal-based inorganic antibacterial coatings at home and abroad and their related preparation processes were reviewed, the problems and improvement methods in the application of these coatings were also discussed, and the development direction of inorganic antibacterial coatings in the future was prospected, such as synergistic antibacterial coatings and bone-promoting antibacterial coatings.

The ZrC-SiC multiphase ceramic precursor of PZCS with abundant active cross-linking sites was prepared by a dehydrocoupling reaction between polyzrocarbonane (PZC) and polycarbosilane (PCS). The ceramization mechanism of PZCS and the composition and structure of the final ceramic were studied. The results reveal that the ceramic yield of PZCS (71.84%, mass fraction, the same below) is significantly higher than that of PZC (51.40%) or PCS (53.46%) precursor at 850 ℃, due to the promoted crosslinking of active groups during the ceramization process. Meanwhile, under the catalysis of Zr-Cp, the short-range carbon and Zr, Si elements are directly converted to carbide ceramics through the synergistic transformation of two polymers in PZCS, avoiding the adverse effects of carbon thermal reduction to the ceramics, and effectively reducing the sintering temperature. The ZrC-SiC nanocomposite ceramic with both high temperature resistance and oxidation resistance components is prepared after pyrolysis of PZCS. The generation of ZrC and SiC phases could inhibit crystallization and refine the grain size, of which the ZrC grain size is 25.4 nm. Moreover, the generation of ZrC-SiC nanocomposite structure would be beneficial for improving the comprehensive performance of ultra-high temperature ceramics.

The compression deformation test on extruded-solid solution 7A43 alloy (Al-6.0Zn-2.1Mg-0.15Cu-0.15Zr, mass fraction/%) was conducted by Gleeble-3500 machine with strain rate of 0.001 s^-1 to 1 s^-1 at room temperature, and the microstructural features were characterized by scanning electron microscopy (SEM), backscattered electron microscopy (EBSD) and X-ray differaction analysis (XRD). It is revealed that with the increase of strain rate, the average grain size decreases due to severe microstructural distortion, whilst the lattice strain and dislocation density in the alloy gradually increase. Dynamic recovery substructure components in the microstructure are enhanced, and the coarse deformed grains are replaced by fine equiaxed grains under high deformation rate conditions. A Fields-Backofen (F-B) constitutive model was constructed based on the experimental stress-strain data, the correlation coefficient (R) and average absolute relative error (AARE) between the experimental and predicted values are 0.991069 and 3.667%, respectively, which provide a good description of the model for deformation rheological behavior of 7A43 aluminum alloy at room temperature.

Lithiumis are considered as an ideal anode material for the next generation high energy density secondary batteries owing to its extremely low reduction potential and high specific capacity. However, its commercial application in lithium metal batteries is hindered by the problems of lithium dendritic growth, volume expansion effect and interface instability. To solve this problems, effective strategies including alloy anode, interface protection, structured anode design and solid electrolyte have been developed. Alloy materials play an important role in above strategies with its superior specific capacity, high Li⁺ conductivity and good lithium affinity. The electrochemical properties of alloy were reviewed and the recent research development of alloy materials' application in lithium metal anode was futher discussed. Last, the main existing problems of alloy materials' application in lithium metal anode were summarized and it was pointed out that the basic theoretical research should be strengthened.

W-Zr alloy has the advantages of high density, high strength and high reaction potential, which can not only exert the excellent penetration ability of tungsten-based alloy, but also provide additional damage by using the oxidation reaction of zirconium. W-Zr alloys have shown great application potential in reactive fragment, armor-piercing projectiles, and small caliber projectiles, and have attracted attention both domestically and internationally. The preparation methods, mechanical properties, and reaction characteristics of W-Zr alloy reactive structural materials were summarized in this paper, especially focusing on the penetration ability and energy release characteristics. On the basis, it was proposed that the future development of W-Zr alloys should focus on the regulation of combustion characteristics of W and the improvement of plasticity. Additionally, there is still a lack of systematic research on the synergistic mechanism between the microstructure, mechanical properties, dynamic fracture, and reaction energy release of W-Zr alloys, which requires further improvement through a combination of experimental research and simulation calculations.

The continuous alumina fiber reinforced alumina ceramic matrix composite (Al₂O_3f/Al₂O₃ ceramic matrix composite) have the characteristics of high melting point, high strength, oxidation resistance, etc., which improves oxidation resistance of the existing aerospace thermal components, and is an ideal candidate material for the application in high temperature and aerobic environment. In this paper, firstly, the constituents of Al₂O_3f/Al₂O₃ composites were analyzed, including reinforced fibers, ceramic matrix and interfacial materials. Moreover, the preparation processes of Al₂O_3f/Al₂O₃ ceramic matrix composites such as slurry infiltration, sol-gel method, precursor infiltration and pyrolysis method, were summarized. The influence of preparation process on the properties of alumina ceramic matrix composites was discussed and numerous achievements were listed. Lastly, feasible optimization schemes were proposed for the preparation of Al₂O_3f/Al₂O₃ ceramic matrix composites with high strength and fracture toughness under medium-high temperature load and long service period.

Superoleophobic refers to the phenomenon that the contact angle (CA) of the oil droplet with low surface tension on the solid surface is greater than 150° as well as the sliding angle (SA) is less than 10°. However, due to the low surface tension of organic liquids, the construction of superoleophobic surfaces was relatively difficult. Inspired by springtail, re-entrant structure has become a breakthrough to solve this problem.Together with surface chemical composition modification and surface roughness, it has been introduced into the design and manufacturing system of superoleophobic surface. Several classical wetting models such as Young model, Wenzel model, Cassie-Baxter model were introduced, the design methods of superoleophobic surfaces were elaborated from the structural structure and chemical composition, and the research progress of superoleophobic surface preparation technologies such as electrospinning, sol-gel method, deposition method, etching method and laser processing was discussed, the oleophobic properties of various surfaces under test liquids with different surface tension were summarized. Finally, the research direction of superoleophobic surface was prospected, that is, low cost, simple operation, environmental friendly and excellent physical and chemical properties of the obtained surfaces. The preparation technology of superoleophobic surfaces would be further explored.

Using carbon fiber cloth with different areal densities and tow sizes, two kinds of carbon fiber preforms with same carbon cloth laminated structure were produced through different z-direction stitching methods. Then, C/C-SiC composites were prepared by combining chemical vapor infiltration (CVI) with gas silicon infiltration (GSI). The influence of carbon fiber preform structure on the microstructure and mechanical properties of CVI-GSI C/C-SiC composites was studied. The results show that the density, phase composition, structure, and properties of the two composites prepared from preforms with the same fiber volume fraction and C/C preform density are significantly different. The smaller carbon fiber tow (1K) and carbon cloth surface density (92 g/m²), as well as the larger voids left by lock stitching, provide more sufficient channels for the infiltration of Si vapor in the GSI reaction process. Thus T1 composite finally prepared has low porosity, uniform structure, and higher performance, with bending strength, modulus, and fracture toughness of 300.97 MPa, 51.75 GPa, and 11.32 MPa·m^1/2, respectively. The comprehensive control of the initial preform structure and the C/C intermediate structure is the key to the preparation of high performance C/C-SiC composites by the CVI-GSI process.

Indium tin oxide (ITO) nanocrystals with different shapes and sizes were synthesized by one-pot method, and ITO nanocrystal films were prepared by spin-coating process. The near-infrared spectrum regulation properties of the films prepared by ITO nanocrystals with different morphologies and sizes were studied. The results show that the visible light transmittance of ITO nanocrystal film is 89.2%, and the resistivity is 54 Ω·cm after 5 spin coatings. The films prepared by uniform spherical ITO nanocrystals with an average diameter of (6.88±1.53) nm exhibit the best near-infrared spectrum regulation ability. After applying a voltage of ±2.5 V, the spectrum regulation at 2000 nm is 39.3%, and the optical density change is 0.43. The ITO nanocrystal film maintains high visible light transmittance before and after electrochromism. The electrochromism of ITO nanocrystals is caused by change of frequency and intensity of localized surface plasmon resonance(LSPR) caused by electron injection/extraction, and its electrochromic process is realized by capacitor charging and discharging.

Carbon fiber reinforced silicone resin derived SiOC ceramic (C/SiOC) composite is a high-temperature structural material with good application prospect due to its performance/cost ratio. In order to further reduce the cost, carbon fiber needled felt with low price was selected as the reinforcement, and C/SiOC composites were prepared by precursor impregnation pyrolysis (PIP) process. The hot molding process was introduced in the first cycle of PIP route. By optimizing the concentration of precursor solution, molding temperature and pressure, the fiber volume fraction and matrix content in the first cycle were effectively improved without damaging the structure of needled felt. Accordingly, the bending strength at room temperature and fracture toughness of C/SiOC composites were increased to 331 MPa and 16.0 MPa·m^1/2, respectively. Then the microstructure evolution during the fabrication of C/SiOC composites was evaluated. The results show that SiOC matrix grows in the carbon fiber bundle firstly, then grows from inside to outside of carbon fiber bundle during fabrication. The pores are distributed around Z direction fibers. Porosity of the composites is decreased gradually and pores of the composites transformed from connected ones into isolated ones as the fabrication cycles is increased. When the fabrication cycles reach 8, the porosity of the composites is unchanged basically. At the same time, the densification of composites is completed.