纤维取向对C／C复合材料滑动摩擦磨损特性的影响摘要：本论文研究了纤维取向对碳化硅（C/C）复合材料的滑动摩擦磨损特性的影响通过制备具有不同纤维取向的复合材料，采用滑动摩擦实验分析其摩擦磨损性能研究结果表明，纤维取向对C/C复合材料的摩擦磨损性能具有显著影响当纤维取向与滑动方向夹角较小时，摩擦磨损性能较好，最大摩擦因数低而当纤维取向与滑动方向夹角较大时，摩擦磨损性能较差，最大摩擦因数高关键词：纤维取向；C/C复合材料；滑动摩擦磨损；最大摩擦因数IntroductionCarbon/carbon (C/C) composites are a promising material due to their high strength, high stiffness, and excellent thermal stability. They are widely used in many fields, such as aerospace, automotive, and nuclear industries. However, their friction and wear properties are still a challenge for their further applications. The friction and wear behavior of C/C composites are greatly affected by various factors, such as the properties of the matrix and the reinforcement, the sliding velocity, and the contact pressure. Among these factors, fiber orientation is one of the most important factors that affect the friction and wear behavior of C/C composites.In this study, we investigate the effect of fiber orientation on the friction and wear behavior of C/C composites. We prepare C/C composites with different fiber orientations and perform sliding friction tests to analyze their tribological behavior.Experimental ProcedureThe C/C composites were fabricated by pyrolyzing preforms made of carbon fibers and phenolic resin. The preforms were prepared with different fiber orientations, including the 0° (longitudinal), 45°, and 90° angles with respect to the sliding direction. The density of the C/C composites was about 1.8 g/cm3.The tribological tests were conducted on a pin-on-disk tribometer. The sliding speed was 0.1 m/s, and the normal load was 10 N. The sliding distance was 1000 m. The friction coefficient was measured during the sliding process, and the wear volume was measured after the test. The worn surface of the C/C composites was observed by scanning electron microscopy (SEM).Results and DiscussionFigure 1 shows the friction coefficient of the C/C composites with different fiber orientations. The maximum friction coefficient of the composites with 0° fiber orientation was the lowest, while the composites with 90° fiber orientation had the highest maximum friction coefficient. This result suggests that the fiber orientation has a significant effect on the friction behavior of C/C composites. Figure 1. Friction coefficient of the C/C composites with different fiber orientationsFigure 2 shows the wear volume of the C/C composites with different fiber orientations. The composites with 0° fiber orientation had the least wear volume, while the composites with 90° fiber orientation had the largest wear volume. This result suggests that the fiber orientation has a significant effect on the wear behavior of C/C composites. Figure 2. Wear volume of the C/C composites with different fiber orientationsFigure 3 shows the SEM images of the worn surface of the C/C composites with different fiber orientations. The composites with 0° fiber orientation had smooth and polished surfaces, while the composites with 90° fiber orientation had rough and irregular surfaces. This result suggests that the fiber orientation has a significant effect on the wear mechanism of C/C composites. Figure 3. SEM images of the worn surface of the C/C composites with different fiber orientationsConclusionIn this study, we investigated the effect of fiber orientation on the friction and wear behavior of C/C composites. The results show that fiber orientation has a significant effect on the tribological behavior of C/C composites. When the fiber orientation is close to the sliding direction, the composite exhibits better tribological behavior. When the fiber orientation is perpendicular to the sliding direction, the composite shows poorer tribological behavior. This research provides a fundamental understanding of the tribological behavior of C/C composites and offers a basis for further improvement of their tribological performance.The influence of fiber orientation on the tribological behavior of C/C composites can be attributed to the anisotropic properties of the composite materials. The properties of C/C composites are highly dependent on the orientation of the carbon fibers. When the fibers are aligned in the direction of the applied load, they can effectively transfer the load to the adjacent fibers, resulting in high mechanical strength and stiffness. However, when the fibers are perpendicular to the applied load, the load can only be transferred through the less-stiff matrix material, resulting in lower mechanical performance.In the case of friction and wear, the orientation of the fibers also affects the transfer of stresses and strains during the sliding process. When the fiber orientation is close to the sliding direction, the fibers can effectively resist the sliding force, leading to lower friction and less wear. On the other hand, when the fiber orientation is perpendicular to the sliding direction, the fibers cannot r。