航空材料学报

2019, 39(5)

[Abstract](2727) [PDF 1398KB](32)

Abstract:

Research progress of high temperature microwave-absorbing ceramic matrix composites

Yue HU, Daqing HUANG, Youqiang SHI, Yi ZHANG, Shan HE, Heyan DING

2019, 39(5): 1-12.

[Abstract](5194) [FullText HTML] (2947) [PDF 1402KB](157)

Abstract:
Microwave-absorbing ceramic matrix composites play an important role in the development of heat-resisting stealthy materials due to their excellent high-temperature mechanical property, superior corrosion resistance and oxidation resistance. In this paper, the micro to macromultiscale design principle of microwave-absorbing ceramics is introduced. The latest research progresses of microwave-absorbing materials such as modified SiC ceramics, doped BaFe₁₂O₁₉ (BFO) ceramics, polymer derived ceramics (PDCs), 3D printed porous ceramics/ceramic-honeycombs, multiscale-designed continuous fiber reinforced ceramic matrix composites (CFCMC) and other new ceramic matrix composites are overviewed. The development trend of ceramic matrix composites with integrated structure absorbing is prospected, and the fiber reinforced ceramic matrix composites with multiscale structure design of micro-macro is proposed to be an important development direction in the field of high-temperature stealth materials in the future.

Research progress of BN interphase and its multilayers in SiC_f/SiC composites

Xiaoxu LYU, Zhe QI, Wenqing ZHAO, Zhuyu JIANG, Jinhua YANG, Yiran ZHOU, Hu LIU, Jian JIAO

2019, 39(5): 13-23.

[Abstract](4864) [FullText HTML] (2820) [PDF 831KB](101)

Abstract:
SiC_f/SiC composites are consisted of SiC fibers, SiC matrix and interphase. The interphase can transfer stresses from matrix to SiC fibers and deflects microcracks, at the same time, it protects SiC fibers from chemical erosion during the preparation and use of materials, which plays a very important role in regulating the properties of SiC_f/SiC composites. In this paper, the effects of precursor gas ratio, carrier gas, deposition pressure, temperature on the deposition rate and microstructure of interphase during the chemical vapor infiltration (CVI) process are summarized. It will be the key and difficult point in the research of SiC_f/SiC composite interphase to select appropriate process conditions and prepare BN and its composite multilayer with ideal structure.

Application and prospect of high-performance thermoplastic composites in helicopter structure

Guangchang CHEN, Jianan YAO, Jindong ZHANG, Puhui CHEN, Chunhai CHEN

2019, 39(5): 24-33.

[Abstract](3036) [FullText HTML] (1403) [PDF 1138KB](98)

Abstract:
High-performance thermoplastic composites, due to their high toughness, excellent impact damage resistance and better fatigue resistance, are especially suitable for constructing special helicopter structures such as the landing gear, tail section, rotor hub and transmission drive shaft, which requires high damage-resistant, ballistic-tolerant, anti-fatigue properties. The application of high-performance thermoplastic composites in foreign helicopters is expanding from the application of key laminate structures to honeycomb sandwich structures, and a large number of low-cost and auto-mated manufacturing techniques such as in-situ automated fiber placement (AFP) and low-cost verification techniques such as virtual testing is being used. Limited by the low level maturity of domestic thermoplastic composites technology, high cost and long cycle of the traditional building block verification methods for the new composite system, the application of thermoplastic composites in domestic helicopter is still in initial stage, the performance stability and consistency of thermoplastic composites, supplementary low cost automatic manufacturing process, low density and high temperature core material and high-confidence efficient virtual qualification technology are needed to focus on the future.

Development and application analysis of ceramic composites armor for helicopter

Yue WU, Xudong WANG, Di LIU, Jiongli LI, Jianqiang GUO, Wenbo LI, Haiping ZHANG, Zhen CAO

2019, 39(5): 34-44.

[Abstract](3403) [FullText HTML] (1421) [PDF 972KB](85)

Abstract:
At present, lightweight armour has been fitted in foreign military helicopters for gunships and transport. By contrast, the armor configuration of domestic helicopters is still a big gap compared with Europe and America in the level type, quantity and single aircraft area. With more requirements of new generation military helicopters' projected-retarded survivability are raised, the development of new armor materials has also made great progress at home and abroad. In this paper, the development of composite bulletproof armor for armed helicopters is reviewed, future development needs are summarized, projected-retarded mechanism, selection principle of material and the way of energy absorption in the process of weapons is analyzed, and application prospect in military helicopters of new materials such as functionally graded materials, micro-laminated material, graphene modified ceramic is looked forward. Due to the independent development needs of helicopters in China, it is urgent to develop new advanced lightweight protective materials with excellent performance. Only by developing new armor materials can improve the survivability of our helicopters, meet the requirements of our weapons, and achieve the synchronous development with the world’s advanced helicopter level.

Application of advanced composite materials for UAV

Nannan NI, Kai BIAN, Lu XIA, Weikai GU, Yuefang WEN

2019, 39(5): 45-60.

[Abstract](4196) [FullText HTML] (1951) [PDF 1048KB](227)

Abstract:
In order to meet the needs of high-altitude, long-endurance, high mobility, functional and economic requirement for the future unmanned aerial vehicle(UAV), advanced composite materials have been increasingly applied in UAVs at home and abroad, and even many all-composite UAVs are manufactured. However, there are still some gaps in the proportion and technical level of composite materials used in UAVs in China compared with foreign countries. The cost of composite parts is one of the main factors restricting its application. This paper introduces the development process of UAV at home and abroad, and summarizes the application of composite materials on UAVs. Some key technologies and development trends of UAV composite materials are proposed. Some questions and suggestions are raised on the application of domestic composite materials on drones. For accelerating the application of composite materials in UAV industry in China, it is necessary to design the composite structure based on the process feasibility and stability with introducing foreign automation technology to reduce composite structure cost, actively develop various liquid forming technology, bag vacuum only-out of autoclave(BVO-OoA) materials and technology, and improve the traditional moulding technology research.

Research progress of low-density and high-entropy alloys

Haichao ZHAO, Xiubing LIANG, Yulin QIAO, Jian LIU, Zhenfeng HU, Yongxiong CHEN, Zhibin ZHANG

2019, 39(5): 61-81.

[Abstract](3618) [FullText HTML] (1505) [PDF 1139KB](97)

Abstract:
High-entropy alloy is a new type of alloy, its excellent physical and chemical properties have attracted extensive attention of the researchers. However, the density of traditional HEAs is high, which greatly limits their engineering applications. In order to reduce the density of HEAs, the low-density elements such as Al, Ti, Mg, Li, and C are used to prepare HEAs, then, a series of LHEAs at equal molar or non-equalmolar concentrations is successfully prepared, showing great application potential in the fields of aerospace, energy and transportation. This paper reviews the research progress of LHEAs. The design guidelines and processing techniques of HEAs are analyzed. The phase structures and properties of LHEAs are introduced according to their system characteristics. The future research direction of LHEAs is prospected.

Application of refractory high entropy alloys on aero-engines

Yaoguang WEI, Gang GUO, Jing LI, Yipan ZENG, Jing HE

2019, 39(5): 82-93.

[Abstract](3835) [FullText HTML] (1618) [PDF 1291KB](151)

Abstract:
High strength and low density are the basic requirements for the materials used in the aeronautical field, the engine materials need high temperatures resistance more severely. High entropy alloys (HEAs) containing refractory metal elements with high melting point show excellent material properties at high temperature. At present, more than 120 kinds of refractory high entropy alloys (RHEAs) have been synthesized, and their physical and mechanical properties, such as density, tensile properties, compression properties, elastic modulus and antioxidant properties have been tested experimentally. In this paper, the performance parameters of refractory high entropy alloys and traditional typical aviation materials are summarized, and the density and yield strength limits of refractory high entropy alloys at high temperature are compared, most refractory high entropy alloys show high mechanical strength and microstructure stability.

Ignition resistance and mechanisms of TC11 titanium alloys with flame retardant coating

Guangbao MI, Peixuan OUYANG, Peijie LI, Jingxia CAO, Xu HUANG, Chunxiao CAO

2019, 39(5): 94-102.

[Abstract](2370) [FullText HTML] (1202) [PDF 1946KB](37)

Abstract:
The effect of YSZ+NiCrAl-B.e composite coating on the ignition resistance of TC11 titanium alloy was studied by using the method of friction in oxygen-enriched atmosphere. Combining friction and wear analysis and unsteady heat conduction calculation, the fireproof mechanism of the composite coating was discussed. The results show that the YSZ+NiCrAl-B.e composite coating significantly improves the ignition resistance of the titanium alloy, and its critical ignition oxygen concentration is about 2.3 times than that of the bare titanium alloy. The friction property of the friction pair composed of the titanium alloy and the composite coating is higher than that of the friction pair composed of titanium and titanium alloy; And the effect of NiCrAl-B.e layer on the ignition resistance of the titanium alloy is not obvious. In the process of friction ignition, the YSZ layer can significantly reduce the temperature rise of the titanium alloy substrate though preventing the rapid heat transfer, delaying the ignition of the titanium alloy. In this sense, the YSZ layer is the flame retardant layer in the coating system, and heat barrier is the main fireproof mechanism.

Numerical simulation study on vacuum gravity precision casting of titanium alloy impeller and experimental validation

Xuewen ZONG, Wenjie LIU, Cong XIONG

2019, 39(5): 103-112.

[Abstract](2950) [FullText HTML] (1432) [PDF 1027KB](29)

Abstract:
Aiming at the problems of many internal defects and low molding quality of cast titanium alloy impeller blades, By designed two casting systems, the finite element method is used to numerically simulate the gating system.. The design optimization of casting system was studied during the casting and solidification process. The effects of flow field, temperature field and shrinkage were carried out on the basis of optimal design, and the microstructure and mechanical properties of the casting were tested and analyzed. The results showed that under the condition of vacuum precipitating temperature of 400 ℃, pouring temperature of 1730 ℃, pouring time of 8 s, the bottom injection have good filling and solidification quality, and there is no defect inside the casting; The top-injection structure is filled with a disordered flow field, and there is a gas-filling phenomenon. Concurrently, there are many internal defects in the casting. Therefore, the pouring system of the bottom-injecting multi-risk structure is superior to the top-injection structure. Simultaneously,the castings microstructure is density, The yield strength, elongation and microhardness are 785.5 MPa, 25.5% and 301.67 HBW.The mechanical properties are good, the surface precision is high, meet the requirements of high quality titanium alloy castings

Mechanism of interface morphology of YSZ thermal barrier coating on growth behavior of TGO layer

Jianjiang TANG, Fangli YU, Haihong ZHANG, Yu BAI, Junwen WANG, Yanling LIU

2019, 39(5): 113-119.

[Abstract](3937) [FullText HTML] (1449) [PDF 1049KB](38)

Abstract:
The mechanism of coating interface bulge on the TGO growth behavior was studied by analyzing the rule of TGO growth and the interface stress at the top coat/bond coat interface. The results show that the growth rate of TGO in the convex region of the top coat/bond coat interface is higher than that in the other regions. According to the stress analysis of ANSYS, the interface stress increases (from 185 MPa to 406 MPa) with the increase of roughness (from 10 μm to 20 μm). Additionally, the interfacial stress also increases (from 142 MPa to 574 MPa) with the thickness of TGO layer increasing (from 1.6 μm to 9.3 μm). What’s more, during high temperature oxidation, the convex region of the top coat/bond coat interface is mainly characterized by tensile stress and the depressed region is compressive stress.The tensile stress can promote the rapid growth of TGO layer, while the compressive stress exhibits the inhibition on the growth rate of TGO. In summary, reducing the roughness of bond coat can reduce the interface stress and slow the growth rate of TGO, which ensures the effective bonding strength of the coating. Thus, the stability of the TBCs at high temperature can be improved.

Compression and energy absorption properties of Al foam-filled tube composite structure

Sichao LI, Xudong YANG, Tao AN, Yuanxing ZHENG

2019, 39(5): 120-127.

[Abstract](2754) [FullText HTML] (1472) [PDF 3110KB](37)

Abstract:
The open-cell Al foam was fabricated by space-holder method and Al foam-filled tube was obtained by filling Al foam into Al alloy tube. The influences of wall thickness, bonding method and filling margin on the mechanical and energy absorbing properties of Al foam-filled tubes were investigated by quasi static compression experiment. The mechanical and energy absorption properties of single and composite structures at different strain rates were studied by quasi-static compression and drop impact tests. The results show that in quasi-static compression tests, when the strain is 60%, the energy absorbed of Al foam-filled tube is 122 % of the numerical sum of Al foam and Al foam-filled tube. In the impact test, the impact load of the composite structure is more stable, and it has higher average impact load and stronger energy absorption capability. Therefore, compared with Al foam, Al foam-filled tube has a great improvement in energy absorption both in compression test and impact test.

2019 Vol. 39, No. 5