summary
Advanced material technology is the forerunner of the development of aerospace high-tech equipment, is the key basic technology to support modern industry, penetrates into all aspects of national defense construction, national economic and social life, and has become a technological highland and national defense focus for the development of all countries in the world. This paper reviews and analyzes the technical status and development trend of aerospace advanced structural materials in recent years, and focuses on four aspects: high-performance polymer materials and their composite materials, high-temperature and special metal structural materials, lightweight high-strength metals and their composite materials, and advanced structural ceramics and their composite materials. At the same time, this paper puts forward the prospect of future research and development of aerospace structural materials, and points out the importance of establishing a complete technical system of "production-learning-research-application".
keyword
materials of construction; Composites; polymer materials; superalloys; lightweight, high-strength metals; Structural ceramics
Aerospace structural materials are indispensable pillar materials for national economic development and national defense construction, and are the core materials to support the needs of high-end equipment and major projects, and play a pivotal role in strategic fields such as aerospace and weapons and equipment. With the support of various national plans, the mainland has initially built a research and development and production system for aerospace structural materials, and the products of metals, non-metals and their composite materials have been continuously optimized, and some research results have reached the international advanced level, and the performance, reliability, batch stability and economy of materials have been greatly improved. For example, T300~T800 domestic carbon fiber has achieved industrialized large-scale production, which has strongly supported the development and batch production of major aerospace equipment; The temperature bearing capacity of single-crystal superalloys has been increased from 1050°C in the second-generation single crystal to 1100°C in the fourth-generation single crystal [1], and key components such as domestic powder superalloy turbine disks and baffles have also been used in a number of military and civil aviation engines under development [2]; The localization of 7085 aluminum alloy thick and large cross-section materials and Ti-6Al-4V titanium alloy forgings has solved several problems of key materials for large aircraft [3]; The self-developed anti-oxidation Cf/C, SiCf/SiC high-temperature structural ceramics and their composite materials have effectively guaranteed the development and production of several major equipment [4]. The above typical research progress has strongly supported and promoted the rapid development of mainland aerospace equipment.
In this paper, the technical status and development trend of aerospace advanced structural materials in recent years are reviewed, and the dilemma of this field is clarified. In the face of a new round of development opportunities in the direction of light weight, high strength, temperature and corrosion resistance, low cost, composite and multi-functional, the mainland urgently needs to break the foreign technology blockade and market monopoly, form a systematic independent research and development and support capability, and meet the demand for key structural materials for major aerospace equipment such as aero engines, heavy-duty rockets, and domestic large aircraft.
01
The strategic significance of advanced structural materials for aerospace
"One generation of materials, one generation of equipment" is a true portrayal of the complementary relationship between the development of aerospace technology and its key materials [5]. On the one hand, the national strategic demand accelerates the emergence of new varieties of aerospace materials, promotes the continuous improvement of material properties, the continuous innovation of research methods, and the continuous progress of manufacturing technology; On the other hand, the in-depth development of theory, technology and industry in the field of aerospace materials has also promoted the continuous expansion of its application fields and accelerated the continuous progress of downstream high-end equipment. Therefore, the research and development of aerospace materials not only drives the development of the national new material industry, but also promotes the upgrading of high-end equipment, which has a significant radiation driving effect on the technological progress and economic construction of the whole society.
High-performance polymer materials, high-performance fibers and composite materials are indispensable key strategic materials in high-end equipment manufacturing, aerospace and other fields. At present, the mainland is highly dependent on the import of high-performance polymers and their composite materials, and some key core technologies rely on imports, which poses great hidden dangers to the sustainable and healthy development of related industries. It is of strategic significance to strengthen the research on key scientific and technological issues of high-performance polymers and their composite materials, and establish a sound engineering verification and industrial system, so as to promote the healthy and orderly development of the domestic large cycle and improve the scientific and technological level and national competitiveness of the mainland's advanced manufacturing industry.
High-temperature and special metal structural materials are indispensable key materials in high-end equipment such as aerospace engines, heavy-duty gas turbines, ultra-supercritical thermal power units, and major scientific devices. At present, there is still a gap between the mainland and the international advanced level in the basic research and technology application of high-temperature and special metal structural materials, and there are problems such as dependence on imports, poor quality stability, low technical maturity and high cost of some key materials and special profiles. The construction of an energy power provides key material support.
Lightweight high-strength metals and their composite materials have significant advantages such as low density, high strength and toughness, temperature and corrosion resistance, high electrical conductivity, high thermal conductivity, easy processing and molding, and low comprehensive application cost. The performance level and application status of lightweight and high-strength metals and their composite materials have become an important indicator to measure the advancement of national key development fields such as large aircraft, aero engines, heavy-duty rockets, and hypersonic vehicles. Under the current new international situation, it is imperative to accelerate the development of the mainland's independent technology system of lightweight and high-strength metal materials.
Advanced structural ceramics and their composite materials are the core materials and components of high-end equipment, and play an important role in key fields such as aerospace, information technology, advanced manufacturing, and national defense and military industry. In recent years, Continental's scientific and technological innovation capabilities in the field of structural ceramics and ceramic matrix composites have been continuously improved, but key materials are still "controlled by others", and bottleneck technologies need to be broken through urgently. High-end materials and products such as high-performance structural ceramic materials, inorganic fibers and their composite materials, ultra-high temperature ceramic composite materials, special structural ceramics and composite materials in extreme environments, and new inorganic non-metallic structural materials are restricted by "stuck necks" in many major applications and equipment fields, and the security of the supply chain is greatly affected by international relations. It is urgent to solve the two major problems of supporting key core materials and components and integrating the industrial chain, so as to provide support for the high-quality development of relevant fields in the country.
02
The status quo and development trend of aerospace structural materials technology
Among the aerospace structural materials in service, metal structural materials are still dominant. The United States, the United Kingdom, Germany, Japan and other developed countries occupy a leading position in the world in research, manufacturing, evaluation, application, etc., through the mature application of key technologies such as material calculation and performance prediction, digital simulation and application evaluation, tissue performance and multi-field coupling environmental life assessment, has formed a complete material technology system, with a huge systematic database.
In order to meet the strategic needs of lightweight aerospace vehicles in the future, lightweight and high-strength composite materials technology has developed rapidly, and the improvement of its process plays a crucial role in improving the performance of aircraft, reducing the development and production costs, and improving service reliability [6]. Figure 1 shows the changes in the total number of fuselage materials in the total fuselage structure of key Airbus and Boeing models, and the use of composite materials has increased significantly [7]. The United States, Japan and other developed countries have been leading the world in the research and development of composite materials, engineering level, batch production capacity, product competitiveness and application, and even some high-end products are still in a monopoly position.
2.1 High-performance polymer materials and their composite materials
High-performance polymer materials and their composite materials with aerospace as the application background are usually high-performance fiber-reinforced resin matrix composites, and their raw materials mainly include reinforcing fibers and resin matrixes, and some additive materials that improve the comprehensive mechanical properties of composite materials or give composite materials special functions are often added to the resin matrix, such as toughening agents, flame retardants, electromagnetic wave absorbers and thermal and electrical conductive fillers. Led by aviation companies such as Boeing, Airbus and GE, resin-based composites have gone through the leap from secondary load-bearing structure to main load-bearing structure application, with military aircraft applications reaching 30%~40% of structural mass, civil aircraft consumption reaching more than 50%, and aero engine consumption reaching 15%. In comparison, the amount of C919 used by Continental is only about 12%, and the amount of aero engines is also limited.
Among the thermosetting resin matrix composite systems, high-performance epoxy resin matrix, bismaleimide resin matrix and polyimide resin matrix composites are the three core systems, and they are also the basis for other high-performance structural/functional integration composites. The maximum long-term service temperature of epoxy resin matrix composites in hot and humid environments is usually 130~150°C, and they are mainly used in the fuselage wing and missile wing structure of subsonic or hyposonic vehicles [9]; The maximum long-term service temperature of bismaleimide resin matrix composites in hot and humid environments is 150~180°C, and they are mainly used in the fuselage wing or projectile wing structure of supersonic vehicles [10]; Polyimide composites are mainly used in engine cold-end structures, aircraft adjacent engine structures, or hypersonic aircraft fuselage wings for long-term use at temperatures greater than 250°C or even above 500°C [11].
Compared with thermosetting resin matrix composites, thermoplastic resin matrix composites have the characteristics of good impact resistance, recyclability, repairability, weldability, and indefinite storage at room temperature as prepregs, and are currently mainly used in various types of doors and wing leading edges and other structures that need to resist the risk of frequent impacts, and are gradually applied to large structural parts such as aircraft fairings, elevators, flat tails, business jet wings, and vertical tails [12-13]. At present, the thermoplastic composites used in aerostructures are mainly polyetheretherketone and polyphenylene sulfide series, and their main application models are listed in Table 1 [14-15].
Carbon fiber is one of the core raw materials of resin matrix composites, and is the basis for advanced carbon fiber reinforced resin matrix composites [16]. Through long-term independent research and development, the first generation of carbon fiber in mainland China has been industrialized, for example, domestic T300 carbon fiber for aerospace has achieved stable supply in batches during the "Eleventh Five-Year Plan" period [17]; The mature production technology of T800 series carbon fiber has directly promoted the technological breakthrough and mass production of M40J and M50J carbon fibers, basically formed the second-generation carbon fiber technology system, and also laid the foundation for the breakthrough of key technologies for the preparation of third-generation carbon fibers [18-20]. Intermediate materials such as foreign prepregs and honeycombs are developing synchronously with fibers, and are currently mainly led and monopolized by companies such as Toray in Japan, Hexcel in the United States and Cytec in the United States, occupying a huge share in the international aerospace field.
2.2 Metal structural materials
The United States, the United Kingdom, Germany, Japan and other developed countries occupy a leading position in the world in the research, manufacturing, evaluation and application of metal structural materials, and have formed a complete material system and a perfect material selection technology system, with a huge system database. In contrast, the mainland metal structural materials industry is in a rising period, and there is an urgent need for variety innovation and technological progress.
2.2.1 Superalloys
Figure 2 shows the development trend of Continental deformed superalloys for aero engine and gas turbine disc forgings [21]. The metallurgical quality and dosage of GH4169 alloy used below 650°C continued to improve, becoming a model of "one material for multiple purposes", supporting the mass production and application of third-generation aero engines and other equipment [22]; The new generation of alloys such as GH4169D, GH4065A, and GH4096 with a temperature bearing temperature of 700~750°C have been successfully developed and applied in engineering, supporting the development of fourth-generation aero engines and commercial turbofan engines [23]; Alloys such as GH4720Li and GH7438 have been used in batches in a variety of small and medium-sized engines [24-25]. The development and application of marine gas turbines and rocket engines have led to the development of GH4698, GH4742, GH4202 and other grades [26-28]. In order to meet the application needs of higher generation engines, alloys such as GH4151 and GH4975 with a temperature bearing capacity of more than 800 °C are being developed in the near future, forming a relatively complete age-strengthening deformed superalloy system with a service temperature between 600~900 °C.
With the innovation of manufacturing processes, casting superalloys have developed from equiaxed and directional casting to single crystals, and the temperature-bearing capacity of casting superalloys has gradually improved by eliminating grain boundaries step by step [30]. As the main material for aero-engine blades, the development of cast superalloys has also achieved the continuous improvement of the thrust-to-weight ratio of aero-engines, and Table 2 lists the development history of the materials selected for turbine blades of various generations of aero-engines [31-33]. With the continuous improvement of the performance requirements of superalloys, the space for alloy composition design has become smaller and smaller, and the design of alloy components based on material calculation, high-throughput experiments, machine learning, and other means has become a future development trend, and the optimization of process parameters through simulation has gradually become a general production and preparation method for superalloy parts [34-36].
Powder superalloys have been widely used in the turbine disks of military and civilian advanced aero engines [37]. On the whole, the development trend of nickel-based powder superalloys has the characteristics of "three highs and one low": high strength, high working temperature, high microstructure stability and low fatigue crack propagation rate. European and American countries took the lead in successfully developing the first generation of 650°C high-strength powder superalloys, such as René 95 [38]; The second-generation 750°C damage-tolerant powdered superalloys, such as René88DT et al. [39], and the third-generation high-strength damage-tolerant powdered superalloys, such as ME3 [40]. The fourth-generation powder superalloy is based on the third-generation and achieves higher operating temperature through composition adjustment and process optimization, so that it has the characteristics of high strength, high damage tolerance, and high operating temperature, such as ME501 [41]. At present, the first generation of powder superalloys represented by FGH4095 and the second generation of powder superalloys represented by FGH4096 have been developed, and the third and fourth generations are still being developed and explored [42-44].
In recent years, the continental superalloy system has made remarkable progress in the development and application of demand-driven and technology-driven. However, superalloys involve many disciplines, high component manufacturing requirements, and small fault tolerance, and their mature applications are based on a comprehensive and in-depth understanding of R&D and manufacturing systems and long-term accumulation, so they need to be continuously strengthened in the future.
2.2.2 Ultra-high strength steel
Ultra-high strength steel refers to a high specific strength structural steel with a yield strength of more than 1380MPa [45], which plays an increasingly important role in aerospace, national defense and military industry, and the main application scenarios in the aerospace field are aircraft landing gear, engine shafts, gear bearings, frames, beams, rocket engine housings, etc. The typical materials of aircraft landing gear are mainly 300M and Aermet100 steel, both of which have ultra-high strength of more than 1930MPa. 300M is a low-alloy ultra-high-strength steel, which is widely used in the landing gear of passenger aircraft, large military transport aircraft and fighter aircraft; AerMet100 steel is the best ultra-high strength steel with the best strength and toughness for mature applications, and has been applied to the landing gear of military aircraft such as F22 and F18E/F because of its excellent resistance to stress corrosion cracking and fatigue resistance. In addition, Fe-Ni-based martensitic aging steels have superior strength and toughness due to the precipitation of nano-scale intermetallic compounds during the aging process, and their typical steel grades are 18Ni C250 and C300 steels, which are mostly used in components such as engine spindles and rocket engine housings [46]. The requirements of equipment performance improvement and high load-bearing, low-cost, and weight-reducing design have pushed the aircraft landing gear and spindle materials to a strength level of more than 2200MPa, and GE and Leep engine spindles are made of GE1014 and ML340 steel of 2100~2300MPa, and GC-24 steel with a strength level of 2400MPa has been developed in China. Aerospace bearing gear steel stands for high-strength carburized stainless steel CSS-42L, with a maximum service temperature of 430°C. The super heat-resistant carburizing steel CH2000 under research is the fourth generation of aviation bearing gear steel, with a surface hardness of 65~68HRC after carburizing and heat treatment, a core tensile strength of more than 2000MPa, and a service temperature of up to 450 °C, which is suitable for gears, bearings and transmission shafts and other transmission components of high-power density transmission systems of new generation aero engines and helicopters.
The stress corrosion resistance of ultra-high strength steel is also the focus of research in various countries. QuesTek has developed a new type of secondary-hardened ultra-high-strength stainless steel, FerriumS53, which has good fracture toughness and has been successfully applied to the landing gear components of the U.S. Air Force A-10 attack aircraft [47]. The 10Cr13Co13Mo5Ni3W1VE ultra-high-strength stainless steel independently developed by Continental has been successfully applied to helicopter landing gear structural parts, and its strength and toughness are better than FerriumS53 steel, making it the ultra-high-strength stainless steel with the highest strength level today, and has a wide range of application prospects in the field of aerospace equipment manufacturing [48].
Low-density, high-strength steel, a new concept proposed in recent years, is characterized by a high Al content while adding austenitizing elements to give it good plasticity, such as the most common Fe-Mn-Al-C quaternary system [49]. In order to achieve the goal of reducing the weight and increasing the range of the aircraft, Continental has developed DT510 low-density steel, which has good strength and toughness while reducing the density of the material, compared with the traditional ultra-high-strength steel 30CrMnSiNi2A, DT510 has a density reduction of 13.4% and a yield strength increase of 19.3%.
2.3 Lightweight and high-strength metals and their composite materials
Light high-strength metals and their composite materials are generally in the stage of running or following, and some high-end products still have the situation of "relying on imports and being controlled by others". The United States, Russia and other countries have been leading the world development direction in the research and development, engineering level, batch production capacity, product competitiveness and application fields of light and high-strength metals and their composite materials, and some high-end products occupy a monopoly position. With the support of various national plans, many scientific and technological achievements have been made in domestic light and high-strength metals and their composite materials, and some research results have reached the international advanced level, and the performance, reliability, batch stability and economy of materials have been greatly improved.
2.3.1 Aluminum alloy
In aviation, aluminum alloy is mainly used in the main load-bearing frame, beam, wall plate, joint and skin of the fuselage, wings and tail of the aircraft, Figure 3 shows the application of aluminum alloy in various parts of the aircraft; In terms of aerospace, a large number of advanced aluminum alloys are used in the main load-bearing parts such as large launch vehicle storage tanks, main structures, connections and transition rings. With the advancement of computational materials science technology, first-principles, thermodynamic calculation, kinetic calculation and other methods are gradually applied to the composition design of aviation aluminum alloys, and gradually turn to machine learning methods to predict microstructure evolution laws, phase stability and comprehensive properties. For example, through a combination of computer-aided simulation and experimental verification, Continental has successfully developed an 800MPa-grade ultra-high-strength aluminum alloy [50].
Relying on the support of national large aircraft and other projects, China has made great progress in the molding control of high-quality and large-scale aluminum alloy ingots, successively carried out the design and iterative optimization of casting process parameters, realized equipment upgrading and key technology research, especially in the purification treatment of high-purification melt and homogeneous and low-stress casting molding control [51-53], and developed new processes such as graded intermittent pause casting method [54], which provides a guarantee for the preparation of high-performance aluminum alloy plates, forgings and profiles. In the face of the thorny problem of internal stress in the quenching of aluminum alloy forgings and thick plates, the residual stress control technology of aluminum alloy thick and large cross-section thick plates/free forgings has been basically broken through in China, so as to realize the uniform deformation of ultra-large free forgings and effectively eliminate the residual stress.
With the development of aerospace equipment in a faster, higher and farther direction, higher requirements are put forward for the heat resistance and comprehensive performance of high strength and toughness of aluminum alloys, and it is urgent to carry out the research work of the fourth generation of aviation aluminum alloys. In addition, with the increasingly urgent demand for low cost and high reliability of aerospace vehicles, the overall manufacturing of large components has become an important direction in the field of aerospace manufacturing. For example, the 7449-T7951 thick plate used in the Airbus A380 is used to manufacture integral wing panels through aging forming technology, which greatly shortens the production cycle [59]. The domestic research on the integrated forming technology of super-large aluminum alloy components is still in its infancy, and the industrial application has not yet been realized, which is an important direction for the development of advanced aluminum alloy in the future.
2.3.2 Titanium alloy
The damage-tolerant titanium alloys, represented by the Ti-62222S and Ti-6Al-4VELLI of the United States, have been successfully applied to the F22, the fourth-generation fighter of the United States, and Continental's TC21 and TC4-DT have been applied as key load-bearing components in new aviation aircraft [60]. In the field of high-strength titanium alloys, Continental has developed ultra-high-strength titanium alloys with a tensile strength of ≥ 1500 MPa, an elongation of ≥5%, and a fracture toughness of ≥ 45 MPa·m1/2 [61-62], and a new high-strength titanium alloy Ti-5321 with a fracture toughness better than 80 MPa·m1/2 at a strength level of 1200 MPa [63].
High-temperature titanium alloys have excellent thermal strength and fatigue properties in the range of 500~600°C, and are one of the key materials used in advanced aero engines [64]. Flame retardant titanium alloy is a kind of structural and functional integration material developed in high-temperature titanium alloy to prevent titanium fire. The United States, Russia, the United Kingdom, and China have successively carried out research on flame-retardant titanium alloys: the Ti-V-Cr AlloyC alloy developed in the United States has been applied to F119 and F135 engines; Ti-Cu-Al flame-retardant titanium alloys have been developed in Russia and the mainland, but they have not yet been applied in engineering due to the low operating temperature. The 500°CTB12 alloy developed by Continental based on the Ti-V-Cr system is close to engineering application [65]. Low-temperature titanium alloys are mainly used in aerospace engineering, and the main low-temperature titanium alloys imitated by mainland China are Ti-5Al-2.5Sn, Ti-2Al-1.5Mn, Ti-3Al-2.5V, etc., and CT20 is innovatively developed [66].
2.3.3 Metal matrix composites
Metal matrix composites are composed of three important parts: metal matrix, reinforcing phase and matrix/reinforcing phase interface, and the matrix material is selected according to the characteristics of the alloy and the use of the composite material in practical applications. For example, in the aerospace field, the shells and internal structures of aircraft, satellites, rockets, etc., require materials with light weight, high specific strength, and high specific stiffness, so light alloys such as magnesium alloy and aluminum alloy are mostly selected as the matrix [67-68]. Under the condition that lightweight, high strength, and heat resistance are required at the same time, titanium alloys and intermetallic compounds are selected as the matrix [69-70].
Continental has matured in the preparation, forming and processing of small and medium-sized aluminum matrix composite components, but with the continuous development of the new generation of precision components of aerospace equipment in the direction of large-scale, lightweight and serialization, it is urgent to develop large-size, lightweight, high-modulus and ultra-high-modulus series of aluminum matrix composites. At present, Continental has adopted pressure-free impregnation technology to achieve stable production of large-size ingots, and isothermal open forging technology to achieve plastic forming of high-modulus (≥110GPa) aluminum-based composites [71]. However, there are still some problems in the existing high-modulus and ultra-high-modulus aluminum-based composites, such as single variety, low comprehensive performance, unstable size, uniformity of structure, and preparation process of ingots, and difficulty in controlling the morphology during the plastic forming of large-scale components [72].
Discontinuous fiber/particle-reinforced titanium matrix composites have the advantages of machinability, isotropy, and low cost, and have broad application potential in aerospace fields such as tactical missile parts, rocket engine parts, and satellites, manned spacecraft, and space stations [73]. In-situ self-generated TiB whiskers (TiBw) and TiC particles (TiCp) are considered to be the most excellent reinforcing phases among discontinuous fiber/particle reinforced titanium-based composites, and have been widely used in the aerospace field at home and abroad [74]. For example, Dynamet in the United States uses TiCp/TC4 composites to manufacture hemispherical rocket shells, missile tails, and aircraft engine parts [75]; Continental has developed the TiBw/TC4 series of thin-walled pipes and screw fasteners, the TiBw/TA15 series of pneumatic grilles, and air rudder members [76-77].
Precision instrument systems such as aerospace vehicles have an increasingly urgent demand for metal matrix composites that are designable and easy to achieve structural/functional integration, but their industrial chain is still in the embryonic stage in mainland China, and product serialization and large-scale have not yet been truly realized [78-81].
2.4 Advanced structural ceramics and their composite materials
Advanced structural ceramics and their composite materials are developing in the direction of high performance, large size, long life, ultra-precision and integration. Foreign advanced structural ceramics and their composite materials were developed earlier, so they have great advantages in raw material processing, composition and performance control, preparation and processing technology, etc. In recent years, foreign structural ceramics and their composite materials have mainly developed into high-end applications such as aerospace, integrated circuits, precision machinery, and nuclear energy.
Safran, Rolls-Royce, Pratt & Whitney, GE, and many other European and American companies have carried out applied research work on SiCf/SiC [82-83]. Safran was one of the first airlines to carry out research on ceramic matrix composites, and was the first to design and apply ceramic matrix composites to the outer adjustment plate of the nozzle of the M88 engine, and carried out the flight verification of SiCf/SiC composite air mixing cone in 2015. Rolls-Royce and Pratt & Whitney have focused on a small number of commissioning of SiCf/SiC composites, which have not yet reached the level of mass production. GE is the company that has truly realized the commercial application of SiCf/SiC composites in aero engines so far, which is closely related to its choice of prepreg-infiltration process route with the characteristics of short cycle, low cost, and good industrial applicability. At present, the assessment and verification of SiCf/SiC composite components in different parts of many aero engines in China have been carried out, 1000 high-temperature gas resistance tests of turbine outer ring test pieces have been completed, and the assessment of guide vanes, flame cylinder single head and other components has been passed, and the feasibility of SiCf/SiC components in the application of SiCf/SiC components in engines has been verified.
Secondly, in terms of oxide ceramic (Ox/Ox) composite components, foreign countries have completed the application or verification assessment of multi-model engines, mainly focusing on the tail spray part of the engine [84-86]. GE's Passport20 engine uses an Ox/Ox fairing, exhaust mixer, and center cone to reduce unit fuel consumption by 8 percent. The Ox/Ox composite sealing sheet is installed on the tail nozzle of the F414 engine of the military aircraft, which improves the durability of the high-temperature parts of the engine tail nozzle. Rolls-Royce designed and developed the Ox/Ox composite exhaust nozzle and center cone for the Trent 1000 engine, which successfully completed flight tests on the Boeing 787 airliner, making it the largest Ox/Ox composite component to date. The U.S. military validated Ox/Ox composite tail spray components on exhaust components of Apache light helicopters, resulting in cost savings of more than 45 percent.
In recent years, the mainland has made important progress in the performance research and application verification of advanced structural ceramics and their composite materials, but there is a large gap with developed countries in the construction of material system, preparation and processing technology, etc., and the connection with the typical application fields of major equipment is still not smooth enough, and the industry itself is still facing problems such as insufficient key raw materials, backward manufacturing level and high production costs.
03
Conclusion
In the next few years, the field of materials will focus on the "production-learning-research-use" innovation chain and collaborative innovation of the industrial chain, in order to greatly improve the technology and application level of aerospace structural materials in the mainland.
The development of aerospace structural materials should be guided by the major needs of the country, with the goal of solving major scientific problems in material design and structural regulation, breaking through the technical bottleneck of structural material preparation and application, and obtaining independent intellectual property rights and engineering applications, improving the original innovation ability in the field of advanced structural materials, improving the complete technical system of design, preparation, manufacturing, application, evaluation and life-cycle maintenance of key structural materials, and establishing advanced structural material technology that closely combines "production, learning, research and application". Realize the innovative development and independent support of key core materials in the field of aerospace and high-end equipment.
(The above article comes from the Journal of Aeronautical Materials, author affiliation: AECC Beijing Institute of Aeronautical Materials Key Laboratory of Advanced High Temperature Structural Materials, AECC Beijing Institute of Aeronautical Materials Testing and Evaluation Beijing Key Laboratory of Aeronautical Materials, China Aero Engine Group Key Laboratory of Materials Testing and Evaluation, authors: Zhang Guoqing, Teng Chaoyi)
Reprint: New Materials Today