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Xie W.-J.,AVIC Composite Corporation LTD | Chen M.-W.,AVIC Composite Corporation LTD
Rengong Jingti Xuebao/Journal of Synthetic Crystals | Year: 2016

SiC fiber reinforced SiC matrix (SiC/SiC) composites were prepared by polymer impregnation pyrolysis (PIP) progress with polycarbosilane (PCS) as impregnant and SiC fiber as reinforcement, and the microscopic morphology, phase structure, bending strength and fracture toughness were measured by SEM, XRD, energy spectrum analysis, three-point bending and single edge notched beam techniques. The results show that SiC/SiC composites prepared by PIP progress possess excellent mechanical properties, and the bending strength and fracture toughness reached 400 MPa and 16.5 MPa·m1/2 at room temperature respectively. Moreover, SiC/SiC composites achieved relative stable high temperature properties. As the temperature increasing, the bending strength nearly unchanged, and the fracture toughness decline slightly because of the destruction of the interface layer at 1350℃. © 2016, Chinese Ceramic Society. All right reserved.

Chen X.,Beihang University | Li Z.,Beihang University | Huang X.,Beihang University | Kou Z.,AVIC Composite Corporation LTD
Hangkong Cailiao Xuebao/Journal of Aeronautical Materials | Year: 2016

In order to compare and analyse the effect of two different kinds of forming process on composite mode I interlaminar fracture toughness, the DCB specimens were tested by using hypothesis inspeetion method. A finite element model was also used to simulate the crack propagation process. The results demonstrate that the average of mode I interlaminar fracture toughness from silicon rubber flexible mold forming is a bit higher than that from metal rigid mold forming. Howevers the variance of mode I interlaminar fracture toughness from the two groups shows no significant difference. The crack propagation process of the two forming process is similar. The established finite element model, which is identical to the test results, can predict the process of the crack expansion effectively. © 2016, Editorial Board of Journal of Aeronautical Materials. All right reserved.

Jiang M.,Beijing Institute of Technology | Zhao L.,AVIC Composite Corporation. Ltd | Liu Q.,AVIC Composite Corporation. Ltd | Zhuo P.,AVIC Composite Corporation. Ltd
Fuhe Cailiao Xuebao/Acta Materiae Compositae Sinica | Year: 2013

In the liquid composite molding (LCM), we can use computer-aided simulation to forecast the filling time and process of the resin, which can assist us to design the flow runner of resin. This paper carried on the simulation of Vacuum Assisted Resin Infusion (VARI, a kind of LCM), based on a cap-shaped foam core sandwich structure. According to the Darcy's law, the calculation formula of the permeability is deduced, measuring the permeability include the carbon fiber, suture, the interface of foam and fiber, the sealing edge. Using the measured results, create some viable flow runner project to simulate and analysis. According to the results, we chosen the project with reasonable injection mode and flow runner to manufacture the cap-shaped foam core sandwich structure by VARI process, the result of the nondestructive testing show that internal defect is barely exist in the component, which proved that the simulation is effective.

Avic Composite Corporation Ltd. and Avic Beijing Institute Of Aeranutical Materials | Date: 2013-03-01

The present disclosure provides a plant fiber textile, a laminate with the plant fiber textile and a fabricating method of the laminate. The plant fiber textile has a matrix resin and continuous plant fibers distributed within the matrix resin. The plant fibers are subjected to a surface modification pretreatment including a coupling treatment with a coupling agent and/or a fire retardation treatment with a fire retardant. The laminate has a stack structure including a layer of the plant fiber textile and at least one layer selected from a group consisting of following layers: glass fiber, aramid fiber or carbon fiber non-woven cloth or textile, preferably distributed within the matrix resin; polymer fiber non-woven cloth or textile, preferably distributed within the matrix resin; or polymer foam or rubber material.

Avic Composite Corporation Ltd. and Avic Beijing Institute Of Aeranutical Materials | Date: 2015-01-07

Provided in the present invention are a composite material containing plant fibre fabrics and a preparation method thereof. The composite material comprises matrix resin and plant fibre fabrics distributed in the matrix resin, wherein the plant fibres of the plant fibre fabrics are pre-treated with surface modifications, and the pre-treatment with surface modifications comprises coupling treatment using a coupling agent, and/or surface flame retardant treatment using a flame retardant. The matrix resin comprises biomass matrix resin. The prepared composite material has the properties of green environmental protection, flame retardancy, sound isolation, etc.; and can be used as a cabin or trim component and can be applied to the following fields: the interiors of an airplane, high-speed train, or car, and furniture, etc.

Wu X.,Nanjing University of Technology | Shao G.,Nanjing University of Technology | Shen X.,Nanjing University of Technology | Cui S.,Nanjing University of Technology | Wang L.,Avic Composite Corporation Ltd
RSC Advances | Year: 2016

We have developed a new sol-gel route to synthesise Al2O3-SiO2 composite aerogels with different alumina/silica (Al/Si) molar ratios using an inexpensive inorganic salt. The approach is straightforward, inexpensive, and it produces monolithic mesoporous material with high specific surface area heat-treated at elevated temperatures. The effects of different Al/Si molar ratios and calcination temperatures on the microstructures and properties of Al2O3-SiO2 composite aerogels are investigated in this study. Results show that SiO2 is essentially amorphous, while Al2O3 predominately exists as polycrystalline boehmite for the as-dried composite aerogels. With the increase of Al/Si molar ratios, the morphologies change from connected spheroidal particles to nanometer-sized fibrous particles and web-like microstructures with varying diameters. As the heat treatment temperature increases to 600 °C, structural transition from boehmite to γ-Al2O3 occurs within all the composite aerogels, and mullitization firstly occurs with the Al/Si molar ratio of 1 at around 1000 °C. The specific surface area undergoes an increase-decrease-increase process at 600 °C and 1200 °C for the composite aerogels with different Al/Si molar ratios. The specific surface area is as high as 166 m2 g-1 at 1200 °C for the sample with an Al/Si molar ratio of 8, which is higher than ever reported. The thermal conductivities of mullite fiber mat reinforced aerogel composites at room temperatures are 0.023 W m-1 K-1, 0.029 W m-1 K-1 and 0.025 W m-1 K-1 with the Al/Si molar ratios of 2, 3 and 8, respectively, suitable for efficient thermal insulations uses. © 2016 The Royal Society of Chemistry.

Shao G.,Nanjing University of Technology | Wu X.,Nanjing University of Technology | Kong Y.,Nanjing University of Technology | Shen X.,Nanjing University of Technology | And 4 more authors.
Journal of Alloys and Compounds | Year: 2016

The objective of this research was to develop a high emissivity coating on the low thermal conductivity ZrO2 ceramic insulation, which can be used in a reusable thermal protective system for short-term applications. The effects of SiB6 and heat-treatment time on the microstructures and radiative properties of the TaSi2-SiO2-borosilicate glass composite coatings prepared on fibrous ZrO2 ceramic with slurry dipping and subsequent sintering method were investigated. The coating prepared in the presence of SiB6 with a heat-treatment time of 15 min maintains a dense structure and infiltrates into the ZrO2 substrate, possessing a gradient structure and good compatibility. The emissivity of the coating is up to 0.9 in the range of 0.3-2.5 μm and 0.8 in the range of 3-30 μm at room temperature. The emissivity mechanism regarding electron transition absorption, lattice vibration absorption and the effect of surface roughness on the emissivity is discussed. The increased roughness leads to the increased emissivity, which can be explained by "circular grooves" and "pyramidal grooves" models. After thermal cycling between 1573 K and room temperature 10 times, the weight gain of the coating prepared with SiB6 is only 0.29%. The high emissivity TaSi2-SiO2-borosilicate glass coatings with high temperature resistance show a promising potential for application in thermal insulation materials. © 2015 Elsevier B.V. All rights reserved.

Shao G.,Nanjing University of Technology | Wu X.,Nanjing University of Technology | Kong Y.,Nanjing University of Technology | Cui S.,Nanjing University of Technology | And 3 more authors.
Surface and Coatings Technology | Year: 2015

An integrative insulation consisting of a MoSi2/borosilicate glass coating and a fibrous ZrO2 ceramic substrate was explored for applications up to 1673K. The MoSi2/borosilicate glass coating was prepared using the slurry dipping and subsequent firing method. The thermal shock behavior of the integrative insulation and the evolution of the surface morphology of the coatings for various thermal shock times were evaluated using confocal laser scanning microscopy (CLSM). The results revealed that the as-prepared coatings could maintain the dense structure and infiltrate into the substrate, forming a gradient structure and exhibiting good compatibility and adherence. After thermal cycling between 1673K and room temperature 15 times, the integrative insulation is also without micro cracks and spalling, and the weight loss is only 2.84%, revealing outstanding thermal shock performance. Additionally, the emissivity of the coatings reached 0.8 at room temperature, which was attributed to the synergistic effect of inter band absorption, crystal lattice vibration and the roughness of the coating. The gradual increase in the roughness resulted in the increase of the emissivity in 200-2500nm at room temperature, which was explained with a "circular grooves" model. These results imply that the integrative insulation can be a promising candidate material in high temperature application. © 2015 Elsevier B.V.

Liu Q.,AVIC Composite Corporation Ltd. | Zhao L.,AVIC Composite Corporation Ltd. | Cao Z.,AVIC Composite Corporation Ltd.
Fuhe Cailiao Xuebao/Acta Materiae Compositae Sinica | Year: 2013

The key factors on the fiber volume fraction and thickness uniformity of the composite molded via vacuum assisted resin infusion(VARI) technology were analyzed, i. e. resin flow control, state of preform, state of fabric and viscosity of resin. The effects of the key factors on the thickness and the fiber volume fraction of the composite molded via VARI technology were verified individually by process test. The results of the tests show that the fiber volume fraction and thickness uniformity of the fiber reinforced resin composite laminates are comparable with those of the composite article molded via prepreg/autoclave process, wherein the fiber reinforced resin composite laminates were molded by HFVI (high fiber-volume vacuum infusion) process and BA9914 resin and vacuum treated U3160 unidirectional woven fabrics are used.

Liu S.,AVIC Composite Corporation Ltd. | Liu F.,AVIC Composite Corporation Ltd. | Guo E.,AVIC Composite Corporation Ltd.
Jixie Gongcheng Xuebao/Journal of Mechanical Engineering | Year: 2014

Composite laminates are very sensitive to foreign impact because of their anisotropy and good absorbing ability to impact energy. They may exhibit different impact damage behavior in body under impact loading. Two kinds of specimens-RTM-stitched and prepreg composite laminate, are manufactured to investigate their behaviors of impact damages. The specimens are subjected to a given energy impact. An ultrasonic B-scan is arranged to the specimens by using focal system in order to study behaviors of impact damages in cross-sections of the specimen bodies. Experimental results have demonstrated that interior damaged area is much larger than damage on surface; new damages occur in different inetrlaminar layers with impact energy going into specimen body deeper and deeper, and they evolve not only along interfaces of layers; the distribution and orientation of damages between near- and far-impact point are significantly different; a clear difference in damage behavior between RTM-stitched and prepreg composite laminates is demonstrated very well, and the stitching fiber thread in depth direction of RTM-stitched composite laminate has obvious help on restriction to development of damages along interlaminar interfaces. The results provide very helpful and practical understanding of the damage behavior in different composite laminate bodies. That may motivate to find new mechanism to improve damage behavior of composite laminates. © 2014 Journal of Mechanical Engineering.

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