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Ma R.,China Institute of Technology | Chang X.,China Institute of Technology | Liao Y.,Xian Aerospace Composites Research Institute | Zhang X.,China Institute of Technology
Gaofenzi Cailiao Kexue Yu Gongcheng/Polymeric Materials Science and Engineering | Year: 2016

Comparative studies were carried out on the NOL rings of carbon fiber/epoxy composites cured by microwave (MW) curing technique and thermal curing technique. The curing behavior, microstructure as well as mechanical properties of cured composites were well investigated through a series of methods and equipments including FT-IR, micro-CT system, mechanical tension test machine and SEM. The results show that the curing mechanism for MW curing technique is different from conventional thermal curing technique and the cure cycle is greatly shortened. FT-IR measurements reveal that MWs do not initiate any new chemical reactions during the curing process and both MW and thermally cured composites have the same chemical structure. CT scan analysis indicates that the MW power used in the curing process has significant effect on the void content of cured composites. Moreover, the MW cured composites exhibit lower tensile and interlaminar shear strength as compared to thermally cured counterparts when using same curing temperature, which is mainly ascribed to the higher void content contained in the MW cured composites. Furthermore, the adhension between the fiber and resin is slightly better for MW cured composites compared with thermally cured ones, which is confirmed by SEM micrographs. © 2016, Editorial Board of Polymer Materials Science & Engineering. All right reserved.


Zhang X.-F.,Xian Aerospace Composites Research Institute | Zhang X.,Xian Aerospace Composites Research Institute | Yang X.-J.,Xian Aerospace Composites Research Institute
Guti Huojian Jishu/Journal of Solid Rocket Technology | Year: 2015

The composite of carbon cloth/phenolic resin were treated during the process of impregnation by the modification method of continuous interface ultrasound. The appearance and cross section of the prepreg tape both before and after being prepared by ultrasonic have been analysed by metallographic analysis and scanning electron microscope. The results show that the resin has been dipped into fiber without changing the index data of the tape; and then, the infiltration of the tape and its uniformity have been both improved greatly. The impregnation procedure treated by ultrasound has been studied in terms of fluid dynamics and fluid static as well. The results indicate that the cavitation effect and acoustic stream mixing initiated by ultrasound in the phenolic resin system can generate impacting pressure of 2.29×1011 Pa in the resin system, impel the molecule of resin system to move at the speed of 2.64 m/s. And then, the period of infiltrating carbon fiber has been decreased to 3 min. Finally, the absorption, proliferation, and infiltration of resin on the carbon cloth surface are accelerated realizing well impregnation between the two ingredients. ©, 2015, Journal of Solid Rocket Technology. All right reserved.


Liao Y.-Q.,Xian Aerospace Composites Research Institute | Liu Y.-Q.,Xian Aerospace Composites Research Institute
Proceedings of the International Astronautical Congress, IAC | Year: 2013

In order to obtain effect of preform structure about mechanical properties of carbon/carbon composites, firstly, representative volume element is given; secondly, subprogram of periodic boundary conditions is compiled using periodic boundary conditions as theory basis; lastly, forecast research on mechanical properties of 3D,4D and 5D carbon/carbon composites is carried out using homogenization theory and bilinear cohesive model. As a result, in the condition of preform volume fraction being a constant, axial and in-plane elastic modulus of 3D preform structure material is highest, shear modulus and Poisson ratio of 4D and 5D preform structure material is higher. Copyright © 2013 by the International Astronautical Federation.


Wang X.-J.,Xian Aerospace Composites Research Institute | Hui X.-M.,Xian Aerospace Composites Research Institute | You L.-H.,Xian Aerospace Composites Research Institute
Yuhang Xuebao/Journal of Astronautics | Year: 2010

In this paper, cyanate ester, epoxy modified cyanate ester, epoxy resin and M40J composite's properties of water-enduring at 100°C were studied. The analysis of the rate of water uptake and the changes of mechanical properties before and after immersion was reported. It was found that cyanate ester and its modified system owned lower water uptake and had no apparent changes on mechanical properties. The rate of water uptake of composite is lower than that of the cast, but the tensile modulus and shear strength descend. The main reason is the interface is destroyed.


Pang F.,Xian Aerospace Composites Research Institute | Cui H.,Xian Aerospace Composites Research Institute | Li R.-Z.,Xian Aerospace Composites Research Institute | Li J.,Xian Aerospace Composites Research Institute | And 2 more authors.
Guti Huojian Jishu/Journal of Solid Rocket Technology | Year: 2012

Carbon fiber integral felt and needled felt with non-woven cloth with an initial density of 0.20 g/cm3 and 0.5 g/cm3 respectively were densified by taking natural gas (NG) as main resource gas, and the penetration depth is about 60 mm. The density of needled felt with non-woven cloth reinforced Carbon/Carbon (C/C) composites could reach 1.39 g/cm3 in 144 hours. After 504 h infiltration, integral felt reinforced C/C composites is densified to gain 1.50 g/cm3 density, while density of needled felt with non-woven cloth reinforced C/C composites is 1.71 g/cm3. The deposition rate using natural gas as precursor is about twice the rate of deposition using propylene. The density distribution of C/C composites was studied by industrial CT qualitatively. The results show that with the increase of infiltration time, the density gradient of C/C composites decreases, and the density gradient of needled felt with non-woven cloth reinforced C/C composites is almost uniform and lower than that of integral felt reinforced C/C composites. The microstructure of matrix carbon was investigated by polarized-light microscopy, indicating that pyrolytic carbon belongs to rough laminar. With the increase of heat treatment temperature, the pyrocarbon layer becomes straight and densified.


Ji A.-L.,Northwestern University | Cui H.,Xian Aerospace Composites Research Institute | Li H.-J.,Northwestern University | Cheng W.,Xian Aerospace Composites Research Institute | Ji L.-L.,Xian Aerospace Composites Research Institute
Xinxing Tan Cailiao/New Carbon Materials | Year: 2011

The structural characteristics of a carbon cloth/felt layer needled preform are investigated. X-Y direction tensile strength, Z direction peel-off stress, and the Naval Ordnance Laboratory (NOL) ring-integrated tensile strength were tested. The X-Y direction tensile strength decreased with the increase of needling density. The law of surface density of fiber felt affecting the Z direction stress is not obvious. Peel-off stress of a 3 K carbon cloth/felt needled preform is higher than that of 6 K and 12 K cloth/felt, and the peel-off stress of a diagonal carbon cloth/felt needled preform is better than that of a satin one. There are three different damage modes for the NOL-integrated tensile ring, namely complete rupture, incomplete rupture, and interlayer peel-off. For 3 K satin carbon cloth/felt needling preform, its NOL ring-integrated tensile strength is the lowest and only 3 MPa, and it shows complete rupture. For the 12 K satin carbon cloth/felt needled preform, the damage mode is interlayer peel-off, and for the 6 K satin carbon cloth/felt needled preform, the damage mode is incomplete rupture, and its integrated mechanical performance is excellent. NOL ring-integrated tensile strength is much higher than X-Y tensile intensity for the preforms made by same process.


Li R.,Xian Aerospace Composites Research Institute | Li J.,Xian Aerospace Composites Research Institute | Cui H.,Xian Aerospace Composites Research Institute
Advances in the Astronautical Sciences | Year: 2013

One of the key technologies for the high performance reconnaissance satellites and large-scale space telescopes with reflective mirrors is the fabrication of a very lightweight material with high specific stiffness, low thermal expansion and high thermal conductivity. As the most preferential candidate material, carbon/carbon-silicon carbide(C/C-SiC) composite offers many special advantages, such as: no toxicity, easy assembly, ultra-lightweight capability. Several reinforcement architecture and densification methods including molding randomly oriented milled carbon fibers, needling perform, liquid silicon infiltration (LSI) and chemical vapor reaction (CVR) can be utilized to meet the requirement of preparation of C/C-SiC and are summarized in this paper.


Zhang S.-h.,Northwestern Polytechnical University | He G.-q.,Northwestern Polytechnical University | Liang G.-z.,Northwestern Polytechnical University | Cui H.,Xian Aerospace Composites Research Institute | And 2 more authors.
Applied Surface Science | Year: 2010

A comparison of F-12 aramid fiber with domestic armid fiber III (DAF III) on surface feature was carried out by scanning electron microscope (SEM), atomic force microscopy (AFM), elements analysis and X-ray Photoelectron Spectroscopy (XPS) analysis. It is found that the two aramid fibers are of "skin-core" structure and fibrillar structure. The microfibrils orient along the fiber axis and rather poorly bond in transverse direction. Many defects exist on the surface of two fibers. Carbon, hydrogen, nitrogen and oxygen are the major elements of two aramid fiber. The element content of the same aramid fiber from surface to interior is different. The surface carbon contents of F-12 aramid fiber and DAF III are increased by 10.75% and 9.95% than those in fiber interior respectively, the surface nitrogen content decreased by 9.72% and 27.02% respectively, and the surface oxygen content increased by 13.99% and 37.95% respectively. © 2009 Elsevier B.V. All rights reserved.


Jia Y.,Huazhong University of Science and Technology | Liao D.,Huazhong University of Science and Technology | Cui H.,Xian Aerospace Composites Research Institute | Ji A.,Xian Aerospace Composites Research Institute | And 2 more authors.
Materials and Design | Year: 2016

The initial stress concentration resulting from the needle-punching effect is a fundamental issue in the longitudinal strength model for laminated carbon/carbon composites. In the present work, this stress distribution is obtained by combining the finite difference method with the shear-lag model. The effect of the needled hole size on the stress concentration is investigated. The broken width is more significant than the separated length for the improvement of the stress concentration degree. The increase of the fiber volume fraction is shown to decrease the overload area. Random needling distributions are compared to the ordered one. Few interactions of each needled area are found in the ordered distribution and the stress concentration is decreased in these random needling distributions. Finally it is concluded that the enlarging of each needled hole, especially the accumulation of broken fibers, during the cyclic process of overlaying laminates and punching is the prime reason for tensile strength reduction under the condition of high needling density. © 2016 Elsevier Ltd.


Feng Y.-Y.,Xian Aerospace Composites Research Institute | Cui H.,Xian Aerospace Composites Research Institute | Li R.-Z.,Xian Aerospace Composites Research Institute
Guti Huojian Jishu/Journal of Solid Rocket Technology | Year: 2011

In order to research the property changes of carbon fibers through multi-times high temperature treatment, one kind of domestic carbon fiber and one kind of imported T300 grade carbon fiber were selected and implemented three times high temperature heat treatment at 2500°C. The influence of high temperature treatment and treatment times on the microstructure, linear density, lattice parameters and ash content and other properties were investigated, and the influence of different high temperature treatment times on different carbon fiber properties was discussed. The results show that through three times high temperature treatment, the trend of property changes of two kinds of carbon fibers are similar, and the influence of the first high temperature heat treatment on each carbon fiber is more evident.

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