共查询到19条相似文献,搜索用时 156 毫秒
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本文采用透射电镜(TEM)对碳纤维/聚酰亚胺复合材料(简称CF/PMR-15)界面形态、界面结构进行了TEM分析,结果表明:CF/PMR-15的界面形态、界面结构与CF的表面性质有关,且对CF/PMR-15的宏观性能有一定的影响。 相似文献
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采用聚酰胺-胺(PAMAM)树状分子化学修饰方法制备碳纳米管接枝炭纤维(CF-PAMAM-CNTs)新型增强体。利用X射线光电子能谱(XPS)、扫描电子显微镜(SEM)和原子力显微镜(AFM)对接枝前后CF表面官能团和表面形貌进行表征;利用接触角测量、单丝拉伸方法研究了接枝前后纤维单丝的润湿性能及拉伸强度,并通过微脱黏法分析了其复合材料的界面剪切强度,同时探索了CNTs的最佳接枝量。结果表明,当CNTs接枝量为15%时,CF表面粗糙度提高了180%,表面能提高了300%,拉伸强度提高了22%,复合材料的界面剪切强度提高了178%,这表明CNTs接枝有利于改善CF复合材料的界面性能。 相似文献
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采用超声辅助电泳沉积法,以异丙醇作为溶剂,在连续碳纤维(CF)表面沉积一层氧化石墨烯(GO),对CF表面进行改性。再经200℃高温处理来增强(GO)与CF之间的黏合性,从而增加CF/环氧树脂(EP)复合材料的界面结合强度。利用SEM和AFM对改性前后CF的表面形貌及微观结构变化进行了表征,通过XPS对改性前后CF表面官能团的变化进行了检测。结果表明,在CF表面沉积GO并经200℃处理后,有效地部分还原了GO(RGO),填补或桥联了CF表面缺陷,使改性后CF的拉伸强度提高了34.58%。同时,高温处理使RGO与CF之间生成牢固的化学键,从而提高了RGO与CF之间的结合强度,最终使RGO-CF/EP复合材料的界面剪切强度(IFSS)提高了69.9%。 相似文献
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碳纤维织物增强聚苯硫醚(CFF/PPS)复合材料是重要的热塑性航空复合材料,其难点为提高碳纤维(CF)与基体的浸润性及界面强度。探讨了CF表面修饰对CFF/PPS界面结合强度的影响,对比了热处理去浆及三种表面修饰剂对碳纤维单丝及CFF/PPS复合材料的改性效果。采用X射线光电子能谱分析(XPS)、扫描电子显微镜(SEM)、单丝强度测试、复合材料静力学测试和动态力学分析等手段对CF表面修饰效果进行评价,建立了基于CF表面修饰制备高性能CFF/PPS热塑性航空复合材料的方法。制备的复合材料层间剪切强度达91.4MPa,弯曲强度953.7MPa,拉伸强度797.4MPa,模量68.4GPa,冲击强度58.3kJ/m2,用SEM观察到CF表面包覆大量PPS树脂。 相似文献
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采用HNO3氧化对碳纤维进行表面处理,并制备了碳纤维增强聚乳酸基(CF/PLA)复合材料。研究了脉冲电磁场(PEF)对该条件下CF/PLA复合材料降解特性的影响。结果表明,碳纤维的表面处理对PEF作用下CF/PLA复合材料的吸水率、质量保持率、弯曲强度和剪切强度等均有不同程度的影响。分析表明,碳纤维表面处理形成的酯键在受到PEF作用后存在某种改变,进而导致CF/PLA复合材料界面降解行为的特异性。本研究有望提供一种从材料本身和外部条件协同控制的可降解CF/PLA骨折内固定装置解决方案。 相似文献
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研究了碳纳米管纤维的微观结构和拉伸性能,并进一步分析了其与环氧树脂形成界面剪切强度及微观结构。采用单丝断裂试验测试了碳纳米管纤维/环氧树脂复合材料体系的界面剪切强度,结合单丝断裂过程中的偏光显微镜照片、复合材料的拉曼谱图和断口扫描电镜照片,研究了碳纳米管纤维/环氧树脂复合材料界面的微观结构。结果表明: 碳纳米管纤维/环氧树脂复合材料的界面剪切强度约为14 MPa;在碳纳米管纤维和环氧树脂形成界面的过程中,环氧树脂可以浸渍纤维,形成具有一定厚度的复合相,这种浸渍过程和界面相的形成都有利于碳纳米管纤维与基体之间的连接。 相似文献
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Chunghao Shih Yutai Katoh Keith J. Leonard Hongbin Bei Edgar Lara-Curzio 《Journal of Materials Science》2013,48(15):5219-5224
A novel method to determine the fiber-matrix interfacial properties of ceramic matrix composites is proposed and evaluated; where micro-pillar samples containing inclined fiber/matrix interfaces were prepared from a SiC fiber-reinforced SiC matrix composites and then compression-tested using the nano-indentation technique. This new test method employs a simple geometry and mitigates the uncertainties associated with complex stress state in the conventional single-filament push-out method or tensile unloading–reloading hysteresis loop analysis method for the determination of interfacial properties. Based on the test results using samples with different interface orientations, the interfacial debond shear strength and the internal friction coefficient are explicitly determined and compared with values obtained by other test methods. SEM observation showed that micro compression caused an adhesive type of debonding between the fiber and the pyrolytic carbon interface. The results suggest that the debonding/failure behavior of the micro-pillars followed the Coulomb fracture criterion. The determined interfacial debond shear strength is ~100 MPa, which appears to be smaller than that determined from fiber push-out test for similar composite systems. The difference can be explained by the effect of normal stress (clamping stress) on the apparent interfacial debond shear strength. 相似文献
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《Composites Part A》1999,30(4):445-450
Results are presented that elucidate: (a) the effects of fiber coating on retained fiber strength and mechanical properties of Nicalon-fiber-reinforced SiC matrix composites; and (b) the role of residual stresses in the interfacial bond strength of SiC-fiber-reinforced reaction-bonded Si3N4 matrix composites. For Nicalon-fiber-reinforced SiC matrix composites that were fractured in a flexural mode, retained in-situ fiber strength, ultimate strength and work-of-fracture (WOF) of the composites increased with increasing thickness of the fiber coating and reached maximum values at a coating thickness of ≈0.3 μm. A direct correlation between the variation of in-situ fiber strength and the variation of ultimate strength and WOF of the composites clearly indicates the critical role of the retained in-situ strength of reinforcing fibers in composites. Fiber pushout tests performed on SiC-fiber-reinforced reaction-bonded Si3N4 matrix composites indicate that both debonding and frictional shear stresses decreased with increasing fiber content. These variations are consistent with the variation of residual radial stress on fibers, as measured by neutron diffraction, i.e. residual stresses decreased with increasing fiber content. Because fracture behavior is strongly controlled by interfacial bond strength, which is proportional to the residual radial stress, appropriate control of residual stresses is critical in the design of composites with desired fracture properties. 相似文献
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Jale Tezcan Soydan Ozcan Bijay Gurung Peter Filip 《Journal of Materials Science》2008,43(5):1612-1618
Carbon/carbon composites are well suited to high-friction applications due to their excellent mechanical and thermal properties.
Since interfacial shear strength is critical to composite performance, characterization of fiber/matrix interface is a crucial
step in tailored design of composites. This article presents a hybrid experimental/analytical study to evaluate the interfacial
shear strength (IFSS) of PAN-fiber-reinforced carbon matrix composites. Microstructure was studied by light and high-resolution
transmission electron microscopy (HRTEM). A series of push-out tests were conducted to examine the fiber/matrix debonding
process. The residual fiber displacement was confirmed by scanning electron microcopy (SEM). The validity of the calculated
IFSS value was demonstrated by a simplified analytical approach, where the components contributing to the measured displacement
were analyzed considering the mechanics of the indentation. The method described in this article has been successfully used
for determining the IFSS of PAN-fiber-reinforced carbon matrix composites. 相似文献
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《Composites Science and Technology》1999,59(12):1871-1879
A Monte-Carlo simulation technique based on a finite-element method has been developed in order to clarify the effect of interfacial shear strength on the tensile strength and reliability of fibrous composites. In the simulation a boron/epoxy monolayer composite was modelled, and five hundred simulations were carried out for various interfacial shear strengths. The interfacial shear strength value which raised the average strength of the composite corresponded approximately to the value which reduced the coefficient of variation. This implies the existence of an optimum value of interfacial shear strength which can increase the strength and reliability. The simulated strength and reliability were closely related to the degree and type of damage around a fiber break. That is to say, large-scale debonding caused by a weak interfacial bond and matrix cracking caused by a strong bond reduced the number of fiber breaks accumulated up to the maximum stress, and decreased the strength and reliability. On the other hand, small-scale debonding promoted comparatively the cumulative effect of fiber breaks and played a key role in increasing the composite strength and reliability. 相似文献
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The influence of nano-SiO2 modified epoxy emulsion sizing on the interfacial adhesion properties of carbon fibers reinforced composites was investigated. The interfacial interaction between carbon fibers and the matrix was characterized by X-ray photoelectron spectrometry (XPS), scanning electron microscopy (SEM) and three-point short-beam shear testing. The results showed that the amount of hydroxyl groups was slightly increased on the carbon fibers surface after treatment with nano-SiO2 modified sizing. Compared to the unsized composites, the interlaminar shear strength (ILSS) values for the composites with unmodified sizing and nano-SiO2 modified sizing were increased by 9% and 14%, respectively. The holes and carbon fibers pullout were not observed in their fracture sections. Surprisingly, the fracture section of the composites with nano-SiO2 modified sizing was more compact and the fiber debonding was more difficult. 相似文献
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Lei Chen Hao Jin Zhiwei Xu Jialu Li Qiwei Guo Mingjing Shan Caiyun Yang Zhen Wang Wei Mai Bowen Cheng 《Journal of Materials Science》2015,50(1):112-121
To improve the interfacial properties of carbon fibers/epoxy composites, we introduced a gradient interphase reinforced by graphene sheets between carbon fibers and matrix with a liquid phase deposition strategy. Interlaminar shear strength and flexural strength of the composites are both improved. The interfacial reinforcing mechanisms are explored by analyzing the structure of interfacial phase with linear scanning system of scanning electron microscope and atomic force microscope. Results indicate that carbon element shows a graded dispersion in the interface region and a gradient interface layer with the modulus decreasing from fibers and matrix is found to be built. To verify the effect of gradient interphase on the interfacial properties of composites, the mixture of carbon fiber/graphene/epoxy is sonicated before curing to disperse graphene sheets in matrix homogeneously. As a result, gradient interphase structures are disappeared and interfacial performance of composites is found to be weakened. The role of gradient interface layers in enhancing interfacial performances is further proved from a different angle. 相似文献
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The interlaminar shear strength, interlaminar fracture energy, flexural strength and modulus of extended-chain polyethylene/epoxy composites are improved substantially when the fibres are pretreated in an ammonia plasma to introduce amine groups on to the fibre surface. These property changes are examined in terms of the microscopic properties of the fibre/matrix interface. Fracture surface micrographs show clean interfacial tensile and shear fracture in composites made from untreated fibres, indicative of a weak interfacial bond. In contrast, fracture surfaces of composites made from ammonia plasma-treated fibres exhibit fibre fibrillation and internal shear failure as well as matrix cracking, suggesting stronger fibre/matrix bonding, in accord with the observed increase in interlaminar fracture energy and shear strength. Failure of flexural test specimens occurs exclusively in compression, and the enhanced flexural strength and modulus of composites containing plasma-treated fibres result mainly from reduced compressive fibre buckling and debonding due to stronger interfacial bonding. Fibre treatment by ammonia plasma also causes an appreciable loss in the transverse ballistic impact properties of the composite, in accord with a higher fibre/matrix interfacial bond strength. 相似文献