增材制造连续碳纤维增强金属基复合材料性能

采用增材制造工艺方法进行具有高比强度、密度小等优良性能连续碳纤维增强金属基复合材料的直接制备。研究了连续碳纤维表面改性、路径搭接率、打印喷头温度、基板温度、打印速度等过程处理方法及工艺参数对所制备金属基复合材料抗拉强度的影响。研究结果表明,对连续碳纤维原材料实施表面改性处理,可以实现制备过程中熔融金属基体与连续碳纤维之间的良好浸润复合,以提高复合材料的抗拉强度;增大路径搭接率,可以有效提高增材制造复合材料内部纤维的体积占比,从而增大其抗拉强度;升高打印喷头温度、基板温度、打印速度,可以减小熔融金属表面张力,提高其流动性,并有利于沉积层间实现良好重熔,从而有效避免在已沉积层表面裂纹处和路径搭接区凹坑处形成气孔缺陷,进一步提升复合材料的抗拉强度。     

三维五向编织玻纤/碳纤环氧树脂混杂复合材料冲击性能和冲击后弯曲性能研究

该文研究了三维五向玻纤/碳纤编织混杂复合材料的冲击性能和冲击后弯曲性能,对试样分别进行了落锤冲击试验和三点弯曲试验。研究表明,通过落锤冲击试样发现,冲击后冲击面的损伤比背面的损伤低,冲击背面裂纹主要沿纵向扩展;通过弯曲性能测试得出碳纤维的加入使玻璃纤维复合材料的弯曲模量提高;当轴纱排布为CF∶GF∶CF时,混杂复合材料的抗冲击性能最好,材料的抗冲击性能与混杂方式有关。     

混杂比对交织芳纶碳纤维复合材料力学性能的影响

为了分析混杂比对层内混杂复合材料力学性能的影响,利用交织方式制备芳纶碳纤维混杂增强体织物,并通过交织物纬纱系统中芳纶与碳纤维的纱线配置比例调整碳纤维在增强体结构中的混杂比。采用真空辅助成型技术制备层内混杂结构的芳纶碳纤维混杂（ACFH）复合材料,并对复合材料的拉伸性能、弯曲性能和冲击性能进行测试。结果表明,增强体纬向系统中芳纶与碳纤维的不均质性对ACFC复合材料经方向上的拉伸强度起消极作用;混杂比的增加对ACFC复合材料的纬向拉伸破坏和弯曲损伤具有抑制作用;纬向上,ACFC复合材料的拉伸强度最高提高了近6倍,弯曲强度最小增加了4.04倍;芳纶与碳纤维混杂协同作用有利于ACFC复合材料的抗冲击性能改善,且混杂比存在最佳值。     

体能训练器械引入改性碳纤维复合材料的性能测试研究

采用分子沉淀法在碳纤维表面接枝碳纳米管进行改性，制备了体能训练器械用碳纤维复合材料。对比分析了未改性和接枝改性碳纤维及其复合材料的显微形貌、拉伸性能和冲击性能。结果表明，碳纤维在接枝表面改性后，表面形成了含O和含N的官能团，且随着接枝层数增多，碳纤维表面接枝CNTs逐渐增多，未发生明显团聚。改性碳纤维的单丝拉伸强度、界面剪切强度会得到不同程度提高；经过接枝改性处理后，改性碳纤维复合材料的碳纤维复合材料的冲击形成功、裂纹扩展功和总冲击功都有不同程度提高，且随着接枝改性层数的增加，改性碳纤维复合材料的碳纤维复合材料的冲击形成功、裂纹扩展功和总冲击功都逐渐增大。接枝改性处理有助于提升碳纤维单丝和复合材料的力学性能。     

玻璃纤维与碳纤维混杂复合材料的拉伸及低速冲击性能研究

本文采用真空辅助树脂渗透成型(VARI)工艺成型了0°/90°玻璃纤维经编织物和0°/90°碳纤维经编织物不同混杂比的复合材料板,并探讨了混杂比、混杂方式等因素对碳-玻纤混杂纤维复合材料的拉伸性能及低速冲击性能的影响。研究结果表明:少量碳纤维的加入便可很好地改善纯玻璃纤维材料的拉伸和冲击性能;同种混杂比下,玻璃纤维铺覆表面的层间混杂结构拥有最好的拉伸性能;对于低速冲击性能来说,随着试样中碳纤维含量的增加,冲击能降低,扩展能降低,韧性指数降低,冲击后剩余压缩强度增大;碳纤维、玻璃纤维含量相接近时,玻璃纤维铺覆表面的层间混杂结构表现出较好的抗低速冲击性能;碳纤维、玻璃纤维含量相差较大时,玻璃纤维铺覆表面的夹芯结构的抗低速冲击性能较好。     

纳米SiO2改性环氧树脂碳纤维体育材料及性能试验

针对传统体育器材环氧树脂碳纤维复合材料脆性大、耐冲击性能差的问题,提出用真空辅助树脂传递模塑成型工艺(VATRM)制备用于体育器材的纳米二氧化硅改性环氧树脂碳纤维复合材料,借助电子万能试验机和落锤式冲击实验机研究了该复合材料的横向拉伸性能和抗冲击性能。结果表明:当纳米二氧化硅质量分数为1%时,纳米二氧化硅/环氧树脂复合材料的横向拉伸性能最佳,断裂伸长率为0.5%;横向拉伸强度为41.7 MPa,拉伸模量为79.9 GPa,比纯环氧树脂碳纤维复合材料的横向拉伸强度、拉伸模量分别提高124.2%和12.5%。经纳米二氧化硅改性的环氧树脂碳纤维复合材料最大冲击力为2 216 N,比纯环氧树脂碳纤维复合材料最大冲击力提高了37.2%左右。     

家具设计中碳纤维复合材料的注塑成型与性能研究

为了提升家具设计中碳纤维复合材料的拉伸性能和弯曲性能。采用传统注塑（多浇口进胶）工艺和新型SVG（顺序阀浇口）工艺制备了碳纤维复合材料,考察了碳纤维质量分数和注塑成型工艺参数（熔体温度、模具温度、注射压力、注射速率）对碳纤维复合材料拉伸性能和弯曲性能的影响。结果表明,采用新型SVG工艺可以消除传统注塑成型工艺下的熔接痕缺陷和气穴缺陷;随着碳纤维质量从0增加至25%,不同熔体温度、模具温度、注射压力和注射速率下碳纤维复合材料的弯曲模量先增大后减小,在碳纤维质量分数为20%时取得较好综合性能;随着碳纤维质量分数的增加,熔接痕处试样和非熔接痕处试样的拉伸强度和弯曲模量都表现为先增大后减小,在碳纤维质量分数为20%时取得最大值,且在相同碳纤维质量分数下,非熔接痕处试样的拉伸强度和弯曲模量都明显大于熔接痕处试样。     

湿热环境对碳纤维/环氧复合材料的冲击破坏特性影响

为了研究湿热环境对碳纤维/环氧树脂(CFRP)复合材料抗冲击性能的影响,对碳纤维/环氧复合材料层合板进行70℃水浴处理,采用锥头圆柱形弹体对湿热饱和试样和干燥室温试样进行速度分别为45 m/s、68 m/s、86 m/s的冲击,采用激光测速仪测量冲击前后的速度,然后采用超声C扫描检测系统、超景深三维显微系统、扫描电镜(SEM)等方法对试样的冲击破坏进行检测。实验结果表明:随着冲击速度的增加,试样的破坏投影面积增加;在速度较低时,湿热环境对碳纤维/环氧树脂层合板的损伤孔洞面积影响更大;湿热处理之后的碳纤维/环氧树脂层合板层间性能明显降低。     

碳纤维复合材料引擎盖的轻量化设计

以汽车碳纤维复合材料引擎盖为研究对象，采用碳纤维复合材料为研究材料，以层合板理论为力学数值模拟CAE设计基础，利用ABAQUS软件对单层级试样准静态拉伸试验和典型U形梁结构准静态三点弯试验进行仿真，然后进行了台架模态和抗凹刚度测试。采用概念设计、材料性能试验和工艺设计多阶段联合优化设计的方法，最终在满足各种力学性能和制造工艺要求的前提下，实现碳纤维复合材料引擎盖的轻量化设计。     

CFRP汽车储气罐低速冲击损伤特性分析

将CFRP汽车储气罐的低速冲击过程作为研究对象,建立了CFRP汽车储气罐冲击损伤多尺度分析有限元模型。在宏观层面分析了储气罐工况、冲头质量、冲击速度及碳纤维增强树脂基复合材料中碳纤维的缠绕角度等因素,对储气罐冲击损伤特性的影响。在微观层面,研究了纤维增强相、树脂基体相及界面相等细观组分材料,对复合材料RVE模型的影响。结果表明,背离冲击一侧的复合材料损伤面积大于受冲击侧,损伤的形貌呈不规则分布。复合材料拉伸损伤起始单元的数量约为压缩损伤起始单元数的1/5。复合材料中,当碳纤维[90/90/90/90/90]环向缠绕时,储气罐抗冲击性能较好。复合材料中碳纤维含量约为55%时,CFRP汽车储气罐抗冲击性较优。界面厚度的增加,提高了复合材料的承载能力。     

快速固化环氧树脂/碳纤维复合材料的性能

利用差示扫描量热分析仪研究了一种快速固化环氧树脂体系的固化工艺参数,确定了以真空辅助树脂灌注工艺制备快速固化环氧树脂/碳纤维复合材料的成型方法,并与常规固化环氧树脂体系制备的碳纤维复合材料进行对比,采用傅里叶变换红外光谱仪对两种材料的树脂基体进行了分析,考察了两种复合材料的纤维含量、孔隙率及力学性能,最后通过扫描电子显微镜观察了快速固化树脂基体与碳纤维的界面结合性。结果表明,快速固化树脂在99℃下固化6 min后固化度可达96%,能够大幅缩减碳纤维复合材料的成型时间,以其制备的碳纤维复合材料拉伸强度比常规固化环氧树脂复合材料高11.20%,弯曲强度高16.92%,纵横剪切强度高7.44%,快速固化树脂与碳纤维界面结合性良好。     

Additive manufacturing of Csf/SiC composites with high fiber content by direct ink writing and liquid silicon infiltration

Direct ink writing (DIW) provides a new route to produce SiC-based composites with complex structure. In this study, we additive manufactured short carbon fiber reinforced SiC ceramic matrix composites (Csf/SiC composites) with different short carbon fiber content through direct ink writing combined with liquid silicon infiltration (LSI). The effects of short carbon fiber content on the microstructure and mechanical properties of the DIW green parts and the final Csf/SiC composites were investigated. The results showed that the Csf content played an important role in maintaining the structure of the green parts. As the Csf content increases, the dimension deviation ratio of the sample decreased at all stages. With the Csf content of 40 vol%, the final Csf/SiC composite had low free Si content and high β-SiC content. The maximum density, tensile strength and bending strength of the Csf/SiC composites were 2.88 ± 0.06 g/cm³, 53.68 MPa and 253.63 MPa respectively. It is believed that this study can give some understanding for the additive manufacturing of fiber reinforced ceramic matrix composites.     

Pultruded fiber reinforced thermoplastic poly(methyl methacrylate) composites. Part II: Mechanical and thermal properties

A novel process has been developed to manufacture poly(methyl methacrylate) (PMMA) pultruded parts. The mechanical and dynamic mechanical properties, environmental effects, postformability of pultruded composites and properties of various fiber (glass, carbon and Kevlar 49 aramid fiber) reinforced PMMA composites have been studied. Results show that the mechanical and thermal properties (i.e. tensile strength, flexural strength and modulus, impact strength and HDT) increase with fiber content. Kevlar fiber/PMMA composites possess the highest impact strength and HDT, while carbon fiber/PMMA composites show the highest tensile strength, tensile and flexural modulus, and glass fiber/PMMA composites show the highest flexural strength. Experimental tensile strengths of all composites except carbon fiber/PMMA composites follow the rule of mixtures. The deviation of carbon fiber/PMMA composite is due to the fiber breakage during processing. Pultruded glass fiber reinforced PMMA composites exhibit good weather resistance. They can be postformed by thermoforming, and mechanical properties can be improved by postforming. The dynamic shear storage modulus (G′) of pultruded glass fiber reinforced PMMA composites increased with decreasing pulling rate, and G′ was higher than that of pultruded Nylon 6 and polyester composites.     

Additive manufacturing of high-strength polyamide 6 composites reinforced with continuous carbon fiber prepreg

The additive manufacturing of continuous fiber reinforced thermoplastics (CFRTPs) paves way for the high-strength, light-weight components for variety of load-bearing applications. In this work, the continuous carbon fiber reinforced PA6 (CCF-PA6) composites was successfully printed from the prepreg filament. The prepreg filament was prepared in-house by impregnating the heat-and-acid treated 1 K carbon fiber bundle with the molten PA6. The tensile strength of the prepreg filament, which contained with 40 vol% CF, reached 984 MPa. The unidirectional CCF-PA6 specimens were subsequently 3D-printed with the prepreg filament, and the mechanical strength of those 3D-printed specimens were tunable by adjusting a set of printing parameters, such as layer thickness, hatch spacing and printing temperatures. The highest tensile strength of the specimen reached 555 MPa. Those specimens also exhibited outstanding mechanical strength at elevated temperatures, still reaching 184 MPa at 150°C. The mechanical strength of those specimens was dependent on the content of the fiber. This study can hopefully provide new insights for feedstock design and spur novel ideas in tailoring the mechanical properties of the 3D-printed CFRTPs.     

短碳纤维增强聚丙烯复合材料性能的研究

本文研究了单螺杆挤出机加工短碳纤维增强聚丙烯复合材料（ＣＦＲＰＰ）的性能。结果表明，经表面处理的短碳纤维与ＰＰ复合，得到的材料其拉伸强度、冲击强度和热变形温度有明显提高，成型收缩率显著减小、电性能与半导体相近。本文还结合拉伸断面的电镜照片，比较分析了表面处理前后短碳纤维增强ＰＰ复合材料力学性能的变化。     

碳纤维布/玻纤布增强聚氨酯复合材料的研究

以聚氨酯为基体树脂,分别以碳纤维布、玻璃纤维布和这两种纤维布交替铺叠作为增强材料,采用真空辅助灌注成型工艺制备了4种复合材料.考察了纤维布的铺层结构对复合材料的弯曲、拉伸和冲击性能的影响.结果显示,复合材料的拉伸模量和弯曲模量随碳纤维含量增加而增加,冲击强度则降低.分别采用TGA、DMA和SEM对复合材料的热性能、界面...     

剑麻纤维/长玻纤混杂增强PP复合材料的力学性能研究

采用剑麻纤维(SF)和长玻璃纤维(LGF)混杂增强聚丙烯(PP)复合材料,考察了SF/LGF的比例和含量对PP复合材料力学性能的影响。结果表明:SF/LGF在聚丙烯树脂基体中呈交叉网状分布,这有利于提高复合材料的冲击强度、弯曲模量、拉伸强度和软化点。在SF/LGF质量比为2 2∶,二者总质量分数为30%时,SF/LGF混杂增强PP复合材料的综合力学性能较好。     

Microstructure and properties of CNTs reinforced CVI-pyrocarbon matrix

Pyrocarbon (PyC) matrices were prepared in two kinds of quartz fiber preforms by chemical vapor infiltration (CVI), and then the fibers were leached by HF. Effects of CNTs on the microstructures and mechanical properties of the quartz fiber reinforced carbon composites and PyC matrices, as well as the interface behaviors of the fiber reinforced composites, were discussed. Randomly oriented CNTs reinforced PyC micro-composites account for the pseudo ISO structure and contribute to the mechanical properties of the PyC matrix. Relative strength between reinforcement and matrix and interface bonding significantly affect the mechanical behaviors of the quartz fiber reinforced pyrocarbon composites: Quartz fiber with low strength and strong interface bonding result in limited strengthening effect on flexural strength of the fiber reinforced composite; low strength unidirectional quartz fiber and weak interface bonding in a much stronger matrix result in limited strengthening effect on tensile strength of the composite.     

异形微型碳纤维复合材料对混凝土力学性能的影响

通过轴心拉伸试验考察了棒状、片状(宽、窄)、波浪形这几种异形微型聚丙烯腈(PAN)基碳纤维复合材料对混凝土力学性能的影响。实验表明:碳纤维复合材料的加入可以有效、较大程度地提高混凝土的抗拉强度、强度和抗折强度。其中,与基准混凝土相比,异形微型碳纤维增强混凝土的抗拉强度最大可提高64%;增强混凝土的标号最大可从C40~C45级增加为C60级;随着复合材料比表面积和的增加,增强混凝土的强度和抗折强度最大可分别提高45.6%和50.6%;此外,在相同尺寸及比表面积下,波浪形碳纤维混凝土比片状碳纤维混凝土更难被折断。以上均证明PAN基碳纤维复合材料对混凝土有较好的增韧作用。