High Mach flight has put forward more stringent requirements for the material and structure design of new generation of high-speed vehicles. This paper reviews the application of ceramic matrix composites（CMCs） in the structural design of aircraft from the aspects of selection, application, and evaluation, and then the future development direction is put forward to provide reference for aircraft ceramic matrix composite structure design. The selection criteria and corresponding preparation methods of CMCs in different application scenarios are comprehensively reviewed, the typical applications of CMCs in aircraft structures are systematically introduced, and the evaluation criteria and ground test methods of the materials under near-service conditions are analyzed. To order to meet the future demands of aircraft, it is necessary to integrate computer-aided optimization technology and innovative preparation methods to enhance the temperature resistance and fatigue performance of CMCs. Developing highly reliable, long-life joining techniques and integrated design solutions will fully leverage the advantages of these materials. Additionally, in-situ characterization techniques under multi-physical field coupling need to be developed to obtain the performance evolution behaviour of CMCs in actual use, providing a reliable basis for the lightweight structural design of aircraft.

The types, preparation methods, thermal and mechanical properties of rare earth hafnate materials and their corrosion behaviors exposed to low melting point silicate（CMAS） and high temperature water vapor are summarized. The previous investigations indicate that the rare earth hafnates have the characteristics of low thermal conductivity, excellent high-temperature phase stability and good resistance to CMAS corrosion, which shows a favorable application prospect in the field of thermal/environmental barrier coatings（T/EBCs）. However, in order to overcome the limitations of a single-phase rare earth hafnate exposed to water vapor corrosion and CMAS, it is still necessary to carry out systematic studies on multi-rare earth components/high-entropy rare earth hafnate in the future, and further clarify the mechanism of influence of lattice distortion caused by components on physical and chemical properties of materials. Moreover, the coupled control method of thermal, mechanical and chemical properties of hafnate with integrated functions such as thermal protection, water vapor corrosion resistance and CMAS resistance and their corresponding material preparation processes should be explored.

Advanced materials technology is the forerunner in the development of high-tech aerospace equipment and the key foundational technology supporting the modern industry. It has penetrated into all aspects of national defense construction, national economy and social life, and has become a technological highland and national defense focus that countries all around the world are competing to develop. This article focuses on analyzing the current technological status and development trend of the advanced structural materials in the aerospace field, elaborating on the aspects of high-performance polymer and their composites, high-temperature and special metal structural materials, lightweight high-strength metals and their composites, and advanced structural ceramics and their composites. The analysis results show that the current development and production of aerospace structural materials in China still face various difficulties, such as too much follow-up research and imitation, lack of independent innovation, severe technological blockade, and technical bottlenecks need to be broken. Meanwhile, the prospects for future research and development are proposed, and the significance of establishing the complete technology system of production-learning-research-application is highlighted.

With the proposal of the "dual carbon”goals, using hydrogen as zero-carbon alternative fuel has become an important trend of the aviation industry in the future. In recent years, the hydrogen-fueled aero-engines have garnered significant attention. Superalloys are the most widely used materials in the hot section components of gas turbine engines. The purpose of this review is to provide reference for the research and development of superalloys for hydrogen-fueled aero-engines future use by understanding the effects of hydrogen-related environment on superalloys currently across various fields. Internal/external hydrogen environments, hydrogen permeation（charging）methods, measurement of hydrogen concentration/distribution or stable existence temperature, the influence of hydrogen on tensile strength, the impact of hydrogen on creep/stress rupture and fatigue properties, and the fracture mechanism of hydrogen embrittlement are described. The degradation factors of mechanical properties of superalloys with different composition, manufacturing process, original microstructure, alloying degree and different application fields under hydrogen-related environment are summarized. In general, mechanical properties tests in the external hydrogen environment exhibit more significant hydrogen-assisted mechanical degradations than that in internal hydrogen environments. Superalloys with higher alloying degree exhibit more pronounced hydrogen embrittlement, while the tendency of properties decrease（creep/rupture, fatigue and tensile）in hydrogen at elevated temperature is much less than that at room temperature. The prospects for the mechanical performance evaluation of current superalloys in hydrogen-related environments for hydrogen-fueled gas turbine and the development of new alloys suitable for hydrogen environments are provided. Hydrogen-fueled gas turbine aero-engines may encounter cryogenic temperature hydrogen environment for liquid hydrogen storage, hydrogen environment for cooling, high-temperature/high-pressure hydrogen environment for gas compression, and the impact of combustion products–water vapor（humid）at elevated temperature. Diffusion or permeation of hydrogen in superalloys, the embrittlement and corrosion of alloys in high-pressure hydrogen environments, oxidation and corrosion behavior in high-temperature humid environments, as well as the degradation and protection mechanism for alloys and coatings in the aforementioned multiple coupling environments shall be concerned. It is necessary to establish hydrogen combustion environment experimental facility that closely simulates service conditions to conduct research on the impact of hydrogen-related environment on superalloys and their components. It is also essential to establish a mechanical performance database and standards for currently used key materials in hot section components such as turbine blades and disks for hydrogen related environments, and properly develop new high-temperature structural materials suitable for hydrogen combustion conditions, which will provide support for the application of hydrogen fueled gas turbine aero-engines.

In view of the shortage of conventional design methods of pressure curve in the anti-gravity precision casting and taking the structural characteristics of the casting with variable cross-sections into account, automatic calculation of cross-sectional areas was implemented for the casting and gating system by the secondary development of CAD software, and quantitatively describing the variable feature of cross-sections of casting was realized. Based on Bernoulli and flow conservation equations, the relationship between the filling pressure and the rising speed of metal liquid level was deduced. A new design method of pressure curve based on the automatic calculation of cross-sectional areas of the casting was proposed. The simulation results of anti-gravity casting for nickel-based superalloy demonstrate that, compared with the pressure curve of the conventional design method, the new curve can reduce the peak value of filling speed from 0.611 m/s to 0.439 m/s at the minimum cross-sectional area, the falling range of which is 28.15%. It meant that the new method can effectively avoid the shock and splash of liquid metal, meanwhile, shorten the filling time, then the filling process is fast and stable. The hydraulic experiment and pouring experiment show that the new pressure curve has a smoother filling liquid level and can effectively avoid casting defects. Therefore, it proves the effectiveness of the new pressure curve design method and provides a basis for rational design of anti-gravity pressure curve.

Continuous SiC fiber reinforced titanium matrix（SiC_f/Ti）composite exhibiting high specific strength, high specific modulus and high temperature resistance, shows important application prospects in the aerospace field. In this paper, the development of SiC_f/Ti composite's application, preparation, property control and testing technology is summarized, and the bottleneck problems required to be broken through are raised. SiC_f/Ti composite shows the unidirectional performance advantages, making it suitable for rotating ring parts（bling, turbine disk, etc）, rod parts（turboshaft, connecting rod, fastener, etc）and plate parts（aircraft skin, etc）. The commonly used preparation methods of SiC_f/Ti composite materials are foil-fiber-foil（FFF）method and matrix coating technology（MCT）. FFF is suitable for preparing plate structural parts, and MCT is suitable for winding structural parts, such as rings, disks and shafts. The properties of SiC_f/Ti composite mainly depend on SiC fiber, titanium alloy matrix and fiber/matrix interface. The microstructure and properties of SiC fibers are highly sensitive to the preparation process, and it is one of the research focuses to obtain stable SiC fibers by regulating the reactor structure and deposition conditions. The titanium alloy matrix can be coated on the fiber surface by physical vapor deposition to prepare the titanium alloy precursor wire, which is the key to the subsequent preparation of high-quality components. The interfacial microstructure, thermal stability and mechanical properties of SiC_f/Ti composites are closely related to the coating on the fiber surface, so the control of coating type and structure is an important means to control the interfacial properties of SiC_f/Ti composites. The application of SiC_f/Ti composite materials has promoted the development of non-destructive testing technology, so researchers have carried out the basic research of ultrasonic testing, X-ray testing and acoustic emission in application of composite material testing. In order to realize the wide application of SiC_f/Ti composites, further research work should be carried out in the structural design, low-cost manufacturing, failure analysis and life prediction of composite materials in the future.

The rapid development of aviation equipment such as hypersonic aircraft has put forward higher requirement for the comprehensive properties and application levels of titanium alloys. The properties of titanium alloys prepared by traditional thermal technologies have approached or reached the theoretical limit. Traditional technologies have been difficult to greatly improve the comprehensive properties of titanium alloys, and exploring graphene technology to modify titanium alloys has become an important development direction. However, it is difficult to control the interface reaction of graphene in titanium alloys. How to obtain the graphene/titanium interfaces with high bonding strength is the key to improve the performance of graphene reinforced titanium matrix composites. Based on the analysis of the problems restricting the development of graphene reinforced titanium matrix composites, this paper emphatically introduces the research progresses of microstructures, interface characteristics, static/dynamic mechanical properties, friction and wear properties, oxidation resistances, and strengthening and toughening mechanisms. The advantages and disadvantages of current solutions for dispersion uniformity, interface bonding and microstructure compactness are discussed. The challenges of interface control technology, large-scale preparation technology and performance stability of graphene reinforced titanium matrix composites are pointed out. Finally, it is proposed that such materials should be combined with theoretical calculation technologies, advanced preparation technologies and special function applications to deepen the interface optimization design and controllable preparation, and the application field expansion.

The forced sweat cooling of porous media is an effective way to solve the problem of thermal protection of the leading edge of hypersonic vehicles. The pore structure and performance of porous media have a significant impact on its cooling effect and reliability. Therefore, it is very important to prepare porous materials that meet the requirements of forced sweat cooling. Herein, Ti6Al4V pre-alloyed powders were used as raw materials, and porous Ti6Al4V samples with different open porosity were prepared by compression molding combined with high-temperature sintering. The effect of the sintering temperature and holding time on the microstructures, phase compositions and mechanical properties of the samples were investigated. The results show that increasing the sintering temperature and prolonging the holding time will reduce the open porosity of the material. When the open porosity is high, the pores in the material are connected and the seepage rate is high, while the sample strength is low. When the open porosity is low, large pores in the sample are reduced and the seepage rate decreases, but the strength becomes higher. The porous Ti6Al4V sample with an open porosity of 21.8% shows the best comprehensive performance. When the porous Ti6Al4V sample is used as active thermal protection material, it can withstand flame ablation with an average heat flux of 2.5 MW/m².

Owing to novel design concepts and their unique properties, high-entropy alloy (HEA) has become a hot topic in material science. At present, the studies and applications of high-entropy alloy are still mainly limited to the preparation and synthesis of materials. With its wide application in industry, it must involve the research of high-entropy alloy in welding field. This paper describes the welding of high-entropy alloy with the same material, welding between high-entropy alloy and dissimilar material, and welding between dissimilar material with high-entropy alloy as filler material. The paper focuses on analyzing the welding method, high entropy alloy components, the initial state of welding and welding parameters, and other factors on the joint organization and properties. While the high-entropy alloy is mainly applied as filler material, the high entropy effect and hysteresis diffusion effect for interface controlling are particularly important. Finally, the high-entropy alloy coatings under different preparation methods are analyzed in detail, introducing the cladding process, the addition of microelements, the effect of post-heat treatment, and comparing the wear resistance high-entropy alloy coatings under the laser melting process. By summarizing the research and application of high-entropy alloy in the welding field, it is pointed out that the current problems are that the corresponding standard between high-entropy alloy system and welding process has not been established and the formation mechanism of defects has not been clarified. The future research directions of high entropy alloy in welding field are proposed.

Al-Li alloy has been widely used in aerospace field attribute to the advantages of lower density, higher strength, damage tolerance and corrosion resistance. Dynamic recrystallization phenomena exist in Al-Li alloy during hot deformation. This paper overviews the dynamic recrystallization behavior occurring in hot processing of Al-Li alloy. The research history of dynamic recrystallization is summarized, together with the key factors that influencing the dynamic recrystallization processes including stacking fault energy, grain size, hot processing conditions and secondary particles. The nucleation mechanisms and conditions of discontinuous dynamic recrystallization, continuous dynamic recrystallization and geometric dynamic recrystallization are depicted and analyzed respectively, followed by a discussion on the effects of the forward three dynamic recrystallization mechanisms regarding the mechanical properties and microstructure. Ultimately, the unsolved and challenging scientific and technological issues are highlighted with some aspects desiring further exploration. It is feasible to provide ideas and inspiration for scholars to better comprehend dynamic recrystallization mechanisms during the hot deformation of Al-Li alloy with the assistance of electron backscatter diffraction and transmission electron microscopy characterization methods.