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以T300炭纤维无纬布、网胎为原材料,层叠针刺成型炭纤维预制体,并采用化学气相沉积工艺对预制体进行致密,制成密度为1.55 g/cm3的针刺C/C复合材料。对针刺C/C复合材料的微观结构进行了观察分析,并对材料力学性能进行了测试。结果表明:化学气相沉积致密的针刺C/C复合材料呈现出以层间大量垂直纤维束为节点的类钉板状网状结构,这种特殊结构使材料层间结合更好,材料整个结构更加紧密;针刺C/C复合材料内部纤维被沉积形成的热解炭所包裹,热解炭的织构类型为光滑层(SL)和粗糙层(RL)并存;针刺C/C复合材料的各项力学性能均达到了较高水平,并且高温力学性能比常温力学性能有了很大幅度的提高。 相似文献
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采用6K炭纤维无纬布/网胎交替叠层及12K炭纤维无纬布/网胎交替叠层,在针刺工艺,致密化、热处理工艺完全相同的情况下,制备了密度为1.8g/cm3的热解炭/树脂炭双元基体的两种C/C复合材料产品,考察了针刺预制体结构单元对C/C复合材料性能的影响.结果表明,两种C/C复合材料的热学(垂直方向导热系数)、电学性能及石墨化度基本相当;而针刺6K炭纤维无纬布/网胎预制体C/C复合材料的拉伸、弯曲、压缩、层间剪切强度分别为127MPa,189MPa,263MPa,24.6MPa;其平行方向导热系数为54.6W/m·K,比常规针刺12K炭纤维无纬布/网胎预制体C/C复合材料相应提高了38%,32.2%,32.8%,38.9%,21%,彰显了细化针刺预制体结构单元对C/C复合材料力学性能的显著影响. 相似文献
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采用平均密度不同的预制体制备变密度预制体C/C复合材料,并对应制备了常用的恒密度预制体C/C复合材料.研究了不同结构和不同平均密度的预制体对C/C复合材料压缩性能的影响.实验结果表明,变密度预制体C/C复合材料的压缩强度远远大于相同平均预制体密度的恒密度预制体C/C复合材料,并且随预制体平均密度的增大呈先增大后下降的趋势.由于预制体内部纤维含量的不同分布状态,变密度预制体C/C复合材料的压缩破坏同时呈现出压溃和剪切破坏模式. 相似文献
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建立了C/C预制体孔隙率与C/SiC复合材料组成的关系模型,并通过表征不同孔隙率的C/C预制体气相硅浸渗制备的C/SiC复合材料的组成和力学性能对模型进行了验证。研究发现,实验结果与模型预测结果基本一致。随着C/C预制体孔隙率的增大,C/SiC复合材料的密度出现先上升后下降的规律,力学性能也遵从同样的规律。XRD分析和相含量测试结果均表明复合材料的相含量与模型预测结果基本一致。实验结果与模型预测结果产生偏差的主要原因是裂解碳反应不完全。 相似文献
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《炭素》2018,(4)
采用整体毡预制体、针刺网胎/无纬布叠层预制体和穿刺预制体,通过化学气相沉积法(CVD)结合液相浸渍法(PIP)制备了C/C复合材料,利用MM1000-Ⅱ型摩擦磨损实验机测试了三种不同预制体C/C复合材料的摩擦性能,采用扫描电子显微镜分别观察了三种C/C复合材料的表面形貌,研究发现预制体结构中纤维排布方式及含量影响C/C复合材料的摩擦系数。相同转速下C/C复合材料的摩擦系数随压力的升高而增大;压力相同的条件下C/C复合材料的摩擦系数随着转速提高而增大;高压高转速下针刺网胎/无纬布制备的C/C复合材料摩擦系数较稳定,整体毡制备的摩擦系数虽小但随转速变化波动较大,穿刺预制体制备的摩擦系数大且波动大,说明穿刺这种增强单元相对较粗大的预制体不适合制备摩擦密封领域的精细结构复合材料。 相似文献
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《Ceramics International》2017,43(15):12280-12286
SiC ceramics, for the first time, were toughened with nano scale carbon nanotubes (CNTs) buckypapers and micro scale carbon fibers within this work. The CNTs buckypapers were alternately laminated with carbon fiber fabrics (Cfb) to a preform by needle punched in Z-direction. Afterwards, the buckypaper-Cfb/SiC composites were obtained by infiltrating of SiC into the as-laminated preform via chemical vapor infiltration (CVI). Some effects of different lamination thickness and CVI times on the mechanical properties of the composites were investigated. Results showed that the maximum flexural strength and work of fracture of the buckypaper-Cfb/SiC composites reached 262.4 MPa and 4.15 kJ m−2, respectively, when the thickness reached about 3.50 mm. Compared to Cfb/SiC composites without buckypapers, the strength and work of fracture of the buckypaper-Cfb/SiC composites increased by 19.8% and 111.7%, respectively. Densified composites can be obtained after CVI for 8 times. A main factor affecting the mechanical properties of buckypaper-Cfb/SiC composites is the degree of densification. Introducing nano scale CNTs and micro scale carbon fibers reaches a multiscale co-toughening effect. Meanwhile, a sandwich structure ceramic matrix composite with high-CNT concentration was obtained in this work. 相似文献
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四种用于制备炭/炭(C/C)复合材料的预制体,即1K发布叠层坯体(1#坯体),3K发布叠层坯体(4#坯体),发市 炭纸叠层坯体(2#坯体),特殊炭毡 发布叠层坯体(3#坯本),并探索了预制体结构对C/C复合材料力学性能影响.研究表明:用1#坯体制备的C/C复合材料弯曲强度最高,2#坏体制备的材料弯曲强度最低,随著炭纤维(CF)体积含量的增加,用四种坯体制备的材料弯曲强度增大。确定了弯曲强度的优化配方. 相似文献
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《Ceramics International》2016,42(8):9527-9537
Chopped carbon fiber preform reinforced carbon and SiC dual matrix composites (C/C–SiC) were fabricated by chemical vapor infiltration (CVI) combined with liquid silicon infiltration. The preform was fabricated by repeatedly overlapping chopped carbon fiber web and needle punching technique. A geometry model of the pore structure of the preform was built and reactant gas transportation during the CVI was calculated. The microstructure and properties of the C/C–SiC composites were investigated. The results indicated that the CVI time for densification of the preform decrease sharply, and the model showed the permeability of the preform decreased with the increase of its density. The C/C–SiC exhibited good mechanical characteristics, especially excellent compressive behavior, with the vertical and parallel compressive strength reached to 359(±40) MPa and 257(±35) MPa, respectively. The coefficient of friction (COF) decreased from 0.60 (at 8 m/s) with the increase of sliding velocity, and finally stabilized at ~0.35 under the velocity of 20 m/s and 24 m/s, and the variations of COF were not sensitive to the sliding distance. The wear rates were between 0.012 cm3/MJ and 0.024 cm3/MJ under different velocities. These results showed that the chopped carbon fiber preform reinforced C/C–SiC are promising candidates for high-performance and low-cost friction composites. 相似文献
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Y.G. Tong Z.H. Cai S.X. Bai Y.L. Hu M.Y. Hua W. Xie Y.C. Ye Y. Li 《Ceramics International》2018,44(14):16577-16582
C/C-SiC composites were fabricated via Si-Zr reactive alloyed melt infiltration using various C/C preforms with different porosities as reinforcements. The influence of preform porosities on the microstructure, mechanical strength and ablation resistance of the as-prepared composites were investigated. The results indicated that microstructure and properties of the C/C-SiC composites seriously depended on C/C preform porosities. The composites were mainly composed of carbon, SiC and ZrSi2 phases, while some residual silicon still existed in the composites prepared with very large porosity preforms. Flexural strength of the composites firstly increased with increasing C/C preform porosities, then reached the highest value, 307?MPa, and finally turned to decrease with the further increasing of preform porosities. Densities of the composites increased with increasing preform porosities, while open porosities were generally small below 7%. Linear ablation rates of the composites firstly sharply decreased with increasing preform porosities and then slightly decreased to reach a balance value. In a word, C/C preform porosity was of great significance for reactive melt infiltration of C/C-SiC composites. Densities, microstructure, mechanical strength and ablation resistance of the resulting composites should be comprehensively taken into consideration to choose an optimal preform porosity for fabrication of C/C-SiC composites. 相似文献
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以三维针刺碳毡作为预制体,先采用树脂单向加压浸渍结合热压固化制备了CFRP复合材料,然后通过树脂热解碳化制备出C/C多孔体。文章重点研究了高温热处理对C/C多孔体显微结构的影响。通过扫描电子显微镜观察了材料的显微结构,使用阿基米德方法测定材料的密度和气孔率,并利用压汞仪分析了材料的孔隙分布,利用X射线衍射分析碳基体的石墨化程度。结果显示,高温热处理后材料的密度降低,孔隙率增大;高温热处理没有改变材料中孔隙的类型,但使材料中三类孔隙尺寸均增大;经过高温热处理材料的石墨化度提高,部分块状碳基体转变为片层状石墨碳结构。 相似文献
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Junjie Duan Menghang Zhang Pengju Chen Zhuan Li Liang Pang Peng Xiao Yang Li 《Ceramics International》2021,47(14):19271-19281
Due to the favorable tribological, mechanical, chemical, and thermal properties, carbon fiber reinforced ceramic composites, especially carbon fiber reinforced carbon and silicon carbide dual matrix composites (C/C–SiC), has been considered as high-performance frictional materials. In this paper, current applications and recent progress on tribological behavior of C/C–SiC composites are reviewed. The factors affecting the friction and wear properties, including the content of silicon carbide and carbon matrix, carbon fiber preform architecture, as well as the matrix modification by alloy additives and C/C–SiC composites under various test conditions are reviewed. Furthermore, based on the current status of researches, prospect of several technically available solutions for low-cost manufacturing C/C–SiC composites is also proposed. 相似文献
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以玄武岩针刺非织造织物为增强体,以硼酚醛树脂为基体树脂,采用层压复合工艺制备了复合材料,研究了不同针刺工艺对复合材料力学性能的影响。结果表明,相同针刺工艺条件下,复合材料的拉伸强度随复合层压压力的增加先增大后减小,复合材料的弯曲强度随复合层压压力的增加而线性增强;在一定情况下,增强体的孔隙率对复合材料力学性能的影响高于增强体拉伸强度对复合材料力学性能的影响。 相似文献