短碳纤维增强碳化硅基复合材料的制备

短纤维的分散均匀性一直是短纤维复合材料应用受限的主要原因．采用固相球磨分散和熔融渗硅工艺,可得到均匀分散的短碳纤维增强碳化硅基复合材料．并利用金相显微镜见察复合材料微观形貌,测试复合材料的抗弯强度和断后韧性．     

碳纤维增强SiC陶瓷复合材料的研究进展

碳纤维增强SiC陶瓷基复合材料具有良好的高温力学性能，是航空航天和能源等领域新的高温结构材料研究的热点之一．本文回顾了增强体碳纤维的发展，对材料的成型制备工艺，材料的抗氧化涂层研究进展和现有的一些应用做了综述，并展望了碳纤维增强SiC陶瓷基复合材料以后的研究重点及发展前景．     

三维碳化硅纤维增强碳化硅基复合材料的研究

采用结构为(PyC/SiC)n的多层复合模式的界面层,依次用化学气相渗透法和先驱体转化法相结合的增密工艺制备出三维Nicalon-SiCf/SiC陶瓷基复合材料.所研制的材料具有较高的强度,而且表现出优异的韧性和类金属材料非灾难性断裂特征.复合材料的主要性能指标为:体积密度2.42 g/cm3,弯曲强度530 MPa.     

碳纤维及其复合材料的发展

综述了碳纤维的发明、发展、市场和应用的现状,通过对碳纤维性能的介绍,讨论了碳纤维在制作高性能陶瓷材料方面的进展,并展望了其新的应用领域.     

碳纤维增强碳化硅陶瓷基复合材料的研究进展及应用

碳纤维增强碳化硅陶瓷基复合材料具有密度低、高强度、高韧性和耐高温等综合性能,已得到世界各国高度重视.本文综述了碳纤维的研究进展,C_f/SiC复合材料的制备方法,并分析了各种制备方法的优缺点.概述了C_f/SiC复合材料作为高温热结构材料和制动材料的应用状况.最后,指出了有待解决的问题和今后的主要研究方向.     

二维机织碳纤维/碳化硅陶瓷基复合材料损伤分析

利用声发射技术全程监测二维机织C／SiC复合材料拉伸实验,通过声发射多参数分析法和断口显微观察,结合材料拉伸应力-变曲线,分析了二维机织C／SiC复合材料拉伸损伤演化过程和损伤机理。结果表明：材料拉伸损伤演化经历3个阶段：第一阶段为无损伤阶段,材料无损伤发生;第二阶段为损伤初始阶段．损伤主要为微裂纹开裂．并且微裂纹开裂基本上均匀发生在样品工作段;第三阶段为损伤加速阶段,损伤主要为宏观基体、界面开裂和纤维束断裂．井且集中发生在断口区域。损伤第二阶段与第三阶段的转换点在拉伸强度的76％左右,转换点的确定对二维机织C／SiC复合材料工程应用有重要意义。     

连续碳化硅纤维增强碳化硅陶瓷基复合材料研究进展

碳化硅纤维增强碳化硅陶瓷基(SiC/SiC)复合材料具有轻质、耐高温、抗氧化的优异特性,在航空领域,如航空发动机的热端构件、高温结构功能一体化构件,航天及空天飞行器热防护结构部件、动力系统热端部件等领域具有广泛的应用前景,受到美国、欧洲、日本等国研究人员的广泛关注。本文从组成、制备工艺、加工工艺和考核应用等方面,综述了SiC/SiC复合材料的国内外研究进展,并指出了目前面临的问题和机遇。     

连续碳纤维增韧碳化硅基复合材料数据库

连续碳纤维增韧碳化硅基复合材料(C/SiC)数据库为C/SiC复合材料的研究和应用提供了一个高效的数据存储、管理和访问的平台,实现了从材料制备、试样加工到性能试验的全过程的信息管理,包含了物理性能、力学性能、热物理化学性能等多种类型的数据,并提供了数据管理功能和一些应用工具.系统采用了最先进的软硬件平台以延长系统的生命周期,应用了一些新的数据库技术,如对像数据类型、统一建模语言(UML)等,简化了数据库的逻辑结构.制定了数据规范、约束、触发器等保证数据的完整性和一致性,并建立了严格的安全机制.     

碳纤维增韧碳化硅基复合材料制备技术的研究进展

碳纤维增韧碳化硅基复合材料具有低密度、高硬度、高强度、类金属特性的断裂韧性等性能,在各行业广泛应用。综述了传统的烧结方法及最新研制开发的联合工艺。展望了未来烧结工艺的发展方向。     

碳纤维增韧碳化硅基复合材料制备技术的研究进展

碳纤维增韧碳化硅基复合材料具有低密度、高硬度、高强度、类金属特性的断裂韧性等性能,在各行业应用广泛。综述了传统的烧结方法及最新研制开发的联合工艺,展望了未来烧结工艺的发展方向。     

Tribo-mechanical properties of composites based on polyoxymethylene reinforced with basalt fiber and silicon carbide whiskers

This paper presents an analysis of the hybrid reinforcement of polyoxymethylene composites. Basalt fibers and monocrystalline silicon carbide fibers were used as reinforcement. Basic tests of mechanical properties were carried out, such as the static tensile and flexural test. The tests were repeated under external factors, such as the influence of water aging and a wide range of exploitation temperatures. The materials were also subjected to tribological tests, that is, determination of the friction coefficient and the specific wear rate. Strength tests revealed an increase in the stiffness of the material as well as a reduction the friction coefficient and abrasive wear. The addition of monocrystalline fibers significantly limited water absorption, stabilized the strength properties in the water environment as well as provided better material's resistance to dynamic impact.     

Effect of heat transfer channels on thermal conductivity of silicon carbide composites reinforced with pitch-based carbon fibers

In this study, silicon carbide (SiC) composites reinforced with pitch-based carbon fibers and composed of heat transfer channels were fabricated by combining chemical vapor infiltration and reactive melting infiltration method. It was observed that the internal heat conduction skeleton of pitch-based carbon fibers was sequentially formed. The thermal conductivities from room temperature to 500 °C along through-thickness direction and in-plane direction were investigated. The results showed that C_pf/SiC composites with heat transfer channels possessed excellent thermal conductvity in two directions, and the thermal conductivity increased with increasing volume content of heat transfer channels. The thermal conductivity in through-thickness direction reached 38.89 W/(m·K), and that for in-plane direction reached 112.42 W/(m·K). Theoretical calculations were empolyed to study the temperature dependence of the C_pf/SiC composites. The variations in slope A′ and intercept B′ values of fitted curves were in good agreement with the experimental results. To verify the reliablilty of the theoretical model, the C_pf/SiC composites were heated at 1650 °C for 2 h and the thermal conductivity exhibited further improvement due to the formation of more perfect crystalline structure. Thermal conductivity through thickness direction improved to 43.49 W/(m·K), and that in in-plane direction improved to 142.49 W/(m·K), which could be identified by the theoretical model. Finally, the leading edge model was established by using ABAQUS finite element analysis software to evaluate the potential application of the composites. Owing to the outstanding thermal conductivity, the leading edge obtained by using C_pf/SiC composites in this study exhibited lower temperature gradient and a more uniform temperature distribution. Moreover, less thermal stress and displacement were generated during heating process.     

Ultra-high-temperature mechanical behaviors of two-dimensional carbon fiber reinforced silicon carbide composites: Experiment and modeling

Carbon fiber reinforced silicon carbide (C/SiC) composites are enabling materials for components working in ultra-high-temperature extreme environments. However, their mechanical properties reported in the literature are mainly limited to room and moderate temperatures. In this work, an ultra-high-temperature testing method for the mechanical properties of materials in inert atmosphere is presented based on the induction heating technology. The flexural properties of a 2D plain-weave C/SiC are studied up to 2600 °C in inert atmosphere for the first time. The deformation characteristics and failure mechanisms at elevated temperatures are gained. Theoretical models for the high-temperature Young’s modulus and tensile strength of 2D ceramic matrix composites are then developed based on the mechanical mechanisms revealed in the experiments. The factors contributing to the mechanical behaviors of C/SiC at elevated temperatures are thus characterized quantitatively. The results provide significant understanding of the mechanical behaviors of C/SiC under ultra-high-temperature extreme environment conditions.     

碳化硅纤维的开发与应用进展

介绍了碳化硅纤维的性能、制备、应用及其现状与发展趋势。     

Damage monitoring of carbon fiber reinforced silicon carbide composites under random vibration environment by acoustic emission technology

Carbon fiber-reinforced silicon carbide (C/SiC) composites are widely used in high-temperature thermo-structural applications. They are subjected to extreme loading conditions, such as random vibrations, which are likely to damage the structure. Structural micro-damage identification during vibration is very difficult, owing to the randomness of the environmental vibration and the complicated response it causes in structures. This study aims to determine a method for monitoring the damage properties of a C/SiC structure under a random vibration environment using acoustic emission (AE) technology. First, a pencil break experiment is conducted to verify the feasibility of the AE technology. Then, an AE monitoring experiment of the structural damage in a vibration environment is systematically conducted. Two types of experiments are designed for simulating the damage formation process inside the structure. In addition, the parameter characteristics of typical AE signals in the random vibration test are analyzed, and the relationships between the AE signal parameters and vibration loading are obtained. Lastly, the different stages of material damage development and damage types in each stage are provided to reveal the damage evolution processes of C/SiC composites. The results indicate that AE technology can be effectively applied to investigate the damage behaviors of C/SiC composites in random vibration environments.     

High-dose,intermediate-temperature neutron irradiation effects on silicon carbide composites with varied fiber/matrix interfaces

SiC/SiC composites are promising structural candidate materials for various nuclear applications over the wide temperature range of 300–1000 °C. Accordingly, irradiation tolerance over this wide temperature range needs to be understood to ensure the performance of these composites. In this study, neutron irradiation effects on dimensional stability and mechanical properties to high doses (11–44 dpa) at intermediate irradiation temperatures (?600 °C) were evaluated for Hi-Nicalon Type-S or Tyranno-SA3 fiber–reinforced SiC matrix composites produced by chemical vapor infiltration. The influence of various fiber/matrix interfaces, such as a 50–120 nm thick pyrolytic carbon (PyC) monolayer interphase and 70–130 nm thick PyC with a subsequent PyC (?20 nm)/SiC (?100 nm) multilayer, was evaluated and compared with the previous results for a thin-layer PyC (?20 nm)/SiC (?100 nm) multilayer interphase. Four-point flexural tests were conducted to evaluate post-irradiation strength, and SEM and TEM were used to investigate microstructure. Regardless of the fiber type, monolayer composites showed considerable reduction of flexural properties after irradiation to 11–12 dpa at 450–500 °C; and neither type showed the deterioration identified at the same dose level at higher temperatures (>750 °C) in a previous study. After further irradiation to 44 dpa at 590–640 °C, the degradation was enhanced compared with conventional multilayer composites with a PyC thickness of ?20 nm. Multilayer composites have shown comparatively good strength retention for irradiation to ?40 dpa, with moderate mechanical property degradation beginning at 70–100 dpa. Irradiation-induced debonding at the F/M interface was found to be the major cause of deterioration of various composites.     

SiC纤维研究进展

本文介绍了近年来碳化硅(SiC)纤维的制备、性能和应用的研究现状及进展，并对今后的研究方向作了简单评述．     

Grinding characteristics and removal mechanisms of unidirectional carbon fibre reinforced silicon carbide ceramic matrix composites

The grinding performance of unidirectional carbon fibre reinforced silicon carbide ceramic matrix composites (C_f/SiC) was investigated in this paper. The effects of the fibre orientation and grinding depth on the surface integrity and grinding forces and an understanding of the grinding mechanisms are the primary concerns of this article. This problem is relatively unexplored; therefore, the main value of this research is to improve the processing quality and reduce the production cost. In the C_f/SiC grinding procedure, cracks, fibre wear, interfacial debonding, fibre pull-out and outcrop can be detected on the ground surface. The grinding depth and deflection angle have been shown to have a notable influence on the surface quality in different datum planes. A suitable grinding depth and deflection angle should be carefully chosen to achieve good surface quality in different machined surfaces. Specifically, the surface quality decreases and the grinding forces increase with increasing grinding depth. In addition, greater grinding surface quality is observed at β?=?90°, i.e., γ?=?0°, but poorer machined surfaces are obtained at α?=?0°, i.e., γ?=?90°. The surface topography, roughness and grinding forces of unidirectional C_f/SiC could be forecasted according to the analysis conclusions. This research is expected to offer guidelines for increasing the machining quality of C_f/SiC.