碳纤维表面涂层对碳纤维增强锂铝硅玻璃陶瓷复合材料热导率的影响

通过溶胶浸渍的方法在碳纤维表面涂覆锂硅溶胶,在高温热处理后,在碳纤维表面形成了二阶和四阶石墨插层化合物。采用涂层处理后碳纤维制备碳纤维增强锂铝硅(Cf/LAS)玻璃陶瓷复合材料。结果表明,碳纤维表面石墨插层化合物的形成,显著提高了Cf/LAS复合材料的热传导能力,提高热压烧结温度有利于热导率的提高。碳纤维表面无涂层处理的Cf/LAS复合材料的热导率在1.1~1.3W/(m·K)之间,碳纤维表面经过涂层处理后,Cf/LAS复合材料的热导率从1.3W/(m·K)提高到2.2W/(m·K),提高了70%。     

C_（sf）／LAS复合材料的制备与力学性能EI

研究了短切碳纤维增强Ｌｉ_２Ｏ－Ａｌ_２Ｏ_３－ＳｉＯ_２玻璃－陶瓷基（以下简称Ｃｓｆ／ＬＡＳ）复合材料的制备工艺及其力学性能。     

TiB2掺杂对碳纤维增强锂铝硅复合材料抗氧化性的影响

目的 研究含有不同质量分数的TiB2的Cf/LAS复合材料的抗弯强度变化规律。方法 以碳纤维、TiB2、硝酸锂、硝酸铝、硅溶胶和氨水为主要原料,采用溶胶凝胶法结合浆料浸渍-热压烧结工艺,制备了加入TiB2的碳纤维增强锂铝硅微晶玻璃（LAS）复合材料Cf/LAS(TiB2),利用XRD、FTIR、万能材料试验机、SEM等对Cf/LAS(TiB2)复合材料的性能和微观结构进行研究。结果 TiB2的质量分数为1%, 3%, 5%, 9%的Cf/LAS(TiB2)复合材料,在1000 ℃热处理30 min后的强度保留率分别为2.9%, 29.1%, 44.0%, 50.0%。结论 材料的强度保留率随TiB2含量的增多而上升,因此Cf/LAS(TiB2)复合材料的抗氧化性随着TiB2含量的增加而增强。     

纤维含量和取向对碳纤维/丁腈橡胶复合材料拉伸和摩擦性能的影响

利用双辊开炼机的压延效应,提高了短切碳纤维/丁腈橡胶中碳纤维的取向度,并对不同碳纤维取向和含量的复合材料的拉伸强度、邵尔硬度、阿克隆磨耗及摩擦系数等性能进行考察。结果表明,随着短切碳纤维的增加,不同碳纤维取向的橡胶复合材料的拉伸强度和拉断伸长率下降,硬度提高,而且平行取向的碳纤维橡胶复合材料拉伸性能较好;随着碳纤维含量的增加,平行取向的碳纤维橡胶复合材料的阿克隆磨耗增加,摩擦系数减小;而随机取向、垂直取向的碳纤维橡胶复合材料阿克隆磨耗先下降后增加,摩擦系数先增加后减小。     

碳纤维网络增强环氧树脂基复合材料的制备与表征

为提高碳纤维/环氧树脂复合材料的刚性和热尺寸稳定性,首先利用短切碳纤维制备了碳纤维网络增强体(CFNR),并将其与环氧树脂复合制备了CFNR/环氧树脂新型复合材料。然后,分别利用扫描电镜和热机械分析仪对CFNR/环氧树脂复合材料的微观结构和热力学性能进行了表征。结果表明:CFNR/环氧树脂复合材料中有明显的网络节点,即碳质粘结点;CFNR/环氧树脂复合材料具有较好的导电性、较高的刚性和较低的热膨胀性,其弹性模量分别为常规短切碳纤维/环氧树脂复合材料及纯环氧树脂的3倍和6倍,平均热膨胀系数(60~200℃)分别为常规短切碳纤维/环氧树脂复合材料的1/15及纯环氧树脂的1/40;随着温度升高,CFNR/环氧树脂复合材料、常规短切碳纤维/环氧树脂复合材料及纯环氧树脂的弹性模量均因环氧树脂变软而降低,当温度高于80℃时,CFNR/环氧树脂复合材料的弹性模量分别约为常规短切碳纤维/环氧树脂复合材料的7倍和纯环氧树脂的近70倍。研究结论可以为开发高刚性、低膨胀聚合物基复合材料提供实验依据和理论指导。     

连续碳纤维增强热塑性复合材料的性能优势及应用举例

该文主要介绍碳纤维增强聚醚醚酮复合材料、碳纤维增强热塑性聚酰亚胺复合材料、碳纤维增强聚苯硫醚复合材料这3种典型的碳纤维增强热塑性复合材料的性能优势,并针对碳纤维增强热塑性复合材料在医疗等民用领域的实际应用情况,对比了连续性碳纤维增强的方式与短切及粉末碳纤维增强方式的效果差异。以连续碳纤维增强聚醚醚酮复合材料骨外科医疗部件为对象,对其耐磨性、生物相容性、耐高温性、X光射线透过性能分别加以说明。     

Csf/BAS玻璃陶瓷复合材料的制备及其力学性能研究

为了提高钡长石(BAS)玻璃陶瓷的力学性能,采用轧膜成型、热压烧结方法制备出纤维分布均匀的致密短碳纤维增强BAS玻璃陶瓷基复合材料(Csf/BAS).采用X射线衍射分析,扫描电子显微镜、透射电子显微镜观察及三点弯曲法与单边开口梁法研究了纤维含量对复合材料组织及力学性能的影响.研究表明:Csf对BAS玻璃陶瓷有良好的强韧化效应.体积分数为30%Csf/BAS复合材料的室温抗弯强度及断裂韧性分别为255 MPa和3.45 MPa.m1/2,其主要的韧化机制为裂纹偏转、纤维的拔出与桥接.用摩尔分数25%Sr代替Ba实现了基体的六方→单斜相的完全转变,进一步提高了复合材料的力学性能.     

基于微观尺度X射线断层扫描技术的短切碳纤维SMC复合材料失效分析

短切碳纤维片状模塑料(SMC)复合材料内部复杂的纤维三维分布及其造成的多样微裂纹演化过程加剧了其失效分析的难度。针对短切碳纤维SMC复合材料的失效行为进行研究, 提出采用微观尺度X射线断层扫描技术实时表征材料内部的微观结构, 捕捉碳纤维和微裂纹的几何信息, 结合先进的图像采集和图像处理技术, 进而准确重构出短切碳纤维SMC复合材料在受力过程中的三维结构变化以及微裂纹的完整演变过程, 定量测量微裂纹的几何尺寸, 实现损伤的精准诊断, 并利用Tsai-Wu失效判据和界面开裂后的基体应力场理论等失效方法探究短切碳纤维SMC复合材料的失效机制。该方法的提出对于研究短切碳纤维SMC复合材料的失效过程以及分析相应的失效行为提供了重要依据。     

短切纤维增强复合材料拉伸强度的预测

在分析单向连续纤维增强复合材料纵向拉伸时细观受力与变形的基础上,对连续纤维的长度和方向进行尺寸和方向性修正,给出了短切纤维增强复合材料的拉伸强度预测公式.使用这个预测公式计算短切碳纤维增强PTFE复合材料的拉伸强度,预测值与实验值吻合得较好.     

短切碳纤维含量对Csf/Al2O3复合材料性能的影响

采用热压烧结法制备了短切碳纤维-氧化铝(Csf/Al2O3)复合材料,研究了短切碳纤维含量对该复合材料维氏硬度、抗弯强度及微波介电性能的影响.结果表明,热压烧结可以获得高致密度、高硬度的Csf/Al2O3复合材料.碳纤维的加入降低了氧化铝基体的抗弯强度,但随着碳纤维含量的增加,抗弯强度有增大的趋势,Csf/Al2O3复合材料复介电常数的实部与虚部也显著提高.     

Effects of fiber orientation angles of fiber-reinforced plastic on sand solid particle erosion behaviors

Solid particle erosion in industrial applications has been a serious problem in many engineering fields. Earlier studies on fiber-reinforced plastic (FRP) composites were mainly focusing on the erosive wear behavior at several different impact angles. However, the effect of fiber orientation on FRP composites has not been thoroughly investigated. Since fiber orientation is one of the important factors in which causing erosive wear damages to FRP composites, in order to understand the virtue of this problem, it is important to investigate the effect of fiber orientation at different impact angles. In this research, the effect of fiber orientation of unidirectional fiber-reinforced plastic composites on erosive wear behavior was studied. Sandblasting-type erosion tests were conducted on the FRP composites with fiber orientation ranging at three impact angles to clarify the relation between fiber orientation and erosive wear behavior. The Dyneema fiber (ductile material) and the carbon fiber (brittle material) were used for the reinforcement fiber in FRP. From the result, it is confirmed that CFRP composites with higher fiber orientation angle erode faster than the composites with lower fiber orientation angle. But the erosion characteristic of DFRP was almost the same regardless of the fiber orientation angle. The damaged surfaces of the FRP composites were then analyzed using scanning electron microscopy and the possible erosion wear mechanisms were investigated.     

超声振动对玻纤增强聚丙烯复合材料注射成型特性的影响

为了研究超声振动对纤维增强复合材料注射成型特性的影响,利用自行开发的超声辅助可视化注射成型实验装置对不同玻纤(GF)含量的GF增强聚丙烯(PP)复合材料进行了超声外场作用下的可视化实验,观测分析了超声功率对复合熔体充填流动行为的影响。此外,通过对试样不同部位的金相观察,分析了超声功率对复合材料纤维取向的影响。结果表明:超声功率会对复合材料注射成型的充填流动行为及制品的纤维取向产生影响,而复合材料纤维含量对超声振动的效果也有直接影响。在纤维含量较低时,超声振动对基体材料微观形态的作用为影响复合材料充填流动性及纤维取向的主因;在纤维含量较高时,超声振动对纤维的作用为影响复合材料充填流动性及纤维取向的主因。研究结果为复合材料超声辅助成型技术的发展提供了依据。     

Electrical characteristics of hierarchical conductive pathways in cementitious composites incorporating CNT and carbon fiber

Cementitious composites incorporating CNT and carbon fiber were produced in the present study, and the effect of the incorporation of carbon fiber on the electrical characteristics of the composites was investigated. Polycarboxylic acid based superplasticizer and silica fume were used to ensure the dispersion of the CNT and carbon fiber. Independent variables were the water to cement ratio, the amount of carbon fiber added to the composites. The test results showed that the cementitious composites incorporating CNT and carbon fiber had more stable electrical resistivity compared to those without carbon fiber. A microstructural analysis was conducted and the mechanism of the improved electrical characteristics of the cementitious composites incorporating CNT and carbon fiber was discussed.     

激光改性纤维对其增强环氧树脂复合材料力学性能的影响

利用激光对玻璃纤维、玄武岩纤维和碳纤维进行表面改性后,以环氧树脂为基体,分别制备三种纤维增强环氧树脂复合材料。利用SEM和万能试验机对表面改性前后的碳纤维形态、力学性能及三种纤维/环氧树脂复合材料的力学性能和断面形貌进行表征,研究了纤维激光表面改性对三种纤维及其增强环氧树脂复合材料力学性能的影响。结果表明:激光表面改性对碳纤维/环氧树脂复合材料的力学性能提升最高,其拉伸强度最大提高了77.06%,冲击强度最大提高了31.25%,玄武岩纤维/环氧树脂复合材料的力学性能提升次之,而玻璃纤维/环氧树脂复合材料的力学性能有所下降。因此,激光进行表面改性适用于碳纤维和玄武岩纤维。     

聚酰亚胺纤维/双马树脂复合材料抗高速冲击性能

采用热压罐成型工艺制备聚酰亚胺纤维/双马树脂复合材料,并采用空气炮冲击实验研究聚酰亚胺纤维体积分数和环境温度对复合材料层板抗高速冲击性能的影响。结果表明:与等面重下TC4钛合金相比,S35聚酰亚胺纤维复合材料抗高速冲击性能更优,且具有优异的高温抗高冲击性能。聚酰亚胺纤维体积分数越高,复合材料层板抗高冲击性能越高,其中,73%体积分数的聚酰亚胺纤维复合材料层板室温弹道吸能可达227.0J,比等面重下TC4钛合金高240%。冲击速率较低时,复合材料弹击面出现周围含纤维分层开裂的圆形凹坑,背弹面出现沿纤维方向的分层开裂;冲击速率较高时,复合材料层板弹击面出现周围含纤维分层开裂的圆形通孔,背弹面出现沿纤维方向大面积纤维分层开裂。     

碳纤维复合材料力学性能研究进展

目的 综述碳纤维复合材料这一热结构材料的力学性能研究进展，推进碳纤维复合材料的研制和应用。方法 采用文献调研法，梳理和汇总国内外有关碳纤维复合材料力学性能的研究内容，对二维复合材料、针刺复合材料及三维编织复合材料3种结构进行性能影响因素分析。结论 影响碳纤维复合材料静态和动态力学性能的因素主要有温度、应变率、密度等，提出应进一步开展碳纤维复合材料在多因素耦合及高温动态性能方面的研究。     

玻璃/苎麻纤维混杂复合材料力学性能研究

混杂纤维增强复合材料由于可以综合利用各种纤维的优点,极大的提高了复合材料的性能,拓展了复合材料的适用范围。本文采用玻璃纤维和苎麻纤维混杂酚醛树脂制备复合材料,研究了复合材料混杂比和铺层顺序对混杂纤维复合材料力学性能的影响。从结果可以看出,玻璃纤维和苎麻纤维的不同比例对混杂复合材料的力学性能有着显著的影响,而采用玻璃纤维作为芯层的时候可以获得较好的拉伸性能,采用苎麻纤维作为芯层的时候可以获得较好的弯曲和剪切性能。     

织物结构对复合材料力学性能影响的试验研究

为探讨不同结构形式织物对复合材料力学性能的影响及其损伤破坏机制之间的差异,通过宏观拉压试验,研究了经编及平纹碳纤维织物增强树脂基复合材料的拉伸及压缩力学性能,并利用声发射对试验过程进行实时监测,对破坏后的断口进行显微镜观察分析,分别给出了两种材料的拉伸和压缩破坏机制.研究结果表明:织物结构形式对复合材料的力学性能有较大影响,与经编织物复合材料相比,平纹织物复合材料的拉伸、压缩强度均较低,且其拉伸、压缩破坏试样的断口相对齐平,分层现象不明显;根据声发射监测结果可以判定两种复合材料损伤过程中的损伤类型,与经编织物相比,平纹织物复合材料拉/压过程中的声发射电压信号相对稳定且整体强度较低.     

Impact of clay nanoparticles on glutaraldehyde crosslinked fiber composites

Glutaraldehyde (GA) was investigated as a potential binder material for nanoparticle-modified wood fiber-based composites. Clay nanoparticle wood fiber composites were fabricated using a wet-lay forming process followed by compression molding. GA treatments significantly increased both bending modulus and strength properties of wood fiber composites. Bending modulus and strength of the fiber composites increased from 2.1 GPa and 16.4 MPa without GA treatment to 6.9 GPa and 49.6 MPa, respectively, after GA treatments. Wood modification with GA also substantially decreased water absorbance and thickness swelling of wood fiber composites. Although there was a significant change in performance after crosslinking, only minimal changes were detected in FTIR analysis of the fiber composites. The effect of montmorillonite clay nanoparticles loading onto wood fiber was found to have a deleterious impact on performance of the wood fiber composites. This research suggests that the nanoparticles inhibit wood fiber–fiber interactions resulting in poor interfiber bonding.     

Analysis of effect of fiber orientation on Young’s modulus for unidirectional fiber reinforced composites

Young’s modulus of unidirectional glass fiber reinforced polymer (GFRP) composites for wind energy applications were studied using analytical, numerical and experimental methods. In order to explore the effect of fiber orientation angle on the Young’s modulus of composites, from the basic theory of elastic mechanics, a procedure which can be applied to evaluate the elastic stiffness matrix of GFRP composite as an analytical function of fiber orientation angle (from 0° to 90°), was developed. At the same time, different finite element models with inclined glass fiber were developed via the ABAQUS Scripting Interface. Results indicate that Young’s modulus of the composites strongly depends on the fiber orientation angles. A U-shaped dependency of the Young’s modulus of composites on the inclined angle of fiber is found, which agree well with the experimental results. The shear modulus is found to have significant effect on the composites’ Young’s modulus, too. The effect of volume content of glass fiber on the Young’s modulus of composites was investigated. Results indicate the relation between them is nearly linear. The results of the investigation are expected to provide some design guideline for the microstructural optimization of the glass fiber reinforced composites.