《碳纤维增强镁基复合材料的制备研究》由会员分享，可在线阅读，更多相关《碳纤维增强镁基复合材料的制备研究（106页珍藏版）》请在金锄头文库上搜索。
1、上海交通大学硕士学位论文 I碳纤维增强镁基复合材料的制备研究碳纤维增强镁基复合材料的制备研究 摘摘 要要 镁合金具有低的密度，高比强度和比模量，良好的阻尼减振性能、电磁屏蔽性和环境相容性等性能，但是模量和强度的绝对值比较低。碳纤维具有低密度、高强度、高模量、低热膨胀、耐辐射等优良特性。以这两种材料复合制备的碳纤维增强镁基复合材料（C/Mg 复合材料） ，将具有密度低、比强度、比模量高、热膨胀系数可以接近于零、在较大温度范围内具有很好的尺寸稳定性等特性，在航空、航天、国防等领域将具有极其广阔的应用前景。复合材料制备中，界面控制和材料成型是两个关键，但碳纤维与镁合金基体的不润湿以及之间的界面反应限
2、制了材料性能的稳定和提高，制备出的复合材料在力学性能上远远低于其期望值。而且镁易燃烧、易氧化，导致镁基复合材料的制备工艺困难。 本文通过分析液相浸渗过程得出 C/Mg 复合材料的制备关键，采用在碳纤维表面制备功能涂层，解决了碳纤维和镁基体的润湿性问题，控摘 要 II制界面反应和界面微观结构；采用纤维与颗粒混杂预制型改善纤维在基体中的分布；采用液相浸渗法，在较低压力下制备获得了界面结合和性能良好的复合材料。 通过分析液相浸渗法制备复合材料时金属熔体对增强体的浸渗过程可知，对于非润湿体系，只有克服临界浸渗压力，才能实现纤维的浸渗。临界浸渗压力与金属液体的表面张力、纤维体积分数和分布等有关。以此为根
3、据提出解决碳纤维增强镁基复合材料制备中浸渗问题的方法，即建立适当的纤维表面涂层和采用纤维与颗粒混杂预制型。 碳纤维表面 SiO2涂层能有效改善碳纤维和镁基体的润湿性。实验采用溶胶凝胶法制备涂层，研究了水硅比、醇硅比、催化剂、化学添加剂对正硅酸乙酯溶胶凝胶过程和碳纤维表面涂层的影响，并讨论了提拉速度、烧结工艺等工艺参数对涂层的影响。利用 SEM、Fourier 红外光谱法、 XRD 等手段对溶胶和涂层进行了测定和分析。 通过选用适当工艺，最终获得连续、均匀的碳纤维表面 SiO2涂层， 选用空心微珠作为在碳纤维的混杂颗粒。空心微珠具有天然球体外形，在起到均匀分散纤维、抵抗束间横向浸渗压力对纤维挤压
4、的同时，避免切割损伤纤维。由于束内纵向充填通道的存在，降低了镁熔体渗入碳纤维过程中的熔体阻力。采用空心微珠碳纤维混杂预制型制备的复合材料实现了碳纤维束内纤维的均匀分散。 通过液相浸渗处理后的碳纤维预制件制备获得复合材料。利用上海交通大学硕士学位论文 IIISEM、TEM、XRD 等分析研究碳纤维和镁基体的界面结合情况、界面产物，测试了复合材料的力学及阻尼性能。 关键词：关键词：溶胶凝胶法、混杂增强、空心微珠、液相浸渗、碳纤维增强镁基复合材料 ABSTRACT IVSTUDY ON THE PREPARATION OF CARBON FIBER REINFORCED MAGNESIUM COMP
5、OSITES ABSTRACT Magnesium and its alloy are one of the lightest engineering materials, whats more, such materials possess of much advantageous properties, such as high specific strength、high specific module，high damping capacity. So, magnesium alloy is important in the studies and applications of th
6、e modern industry. However, it is difficult to apply magnesium alloy in advanced technology field such as spaceflight and aviation because of its low elastic module and low strength. Metal matrix composites could improve the mechanics properties, such as tensile strength etc. Carbon fiber reinforced
7、 magnesium-matrix composites have been strongly considered the most potential lightweight and high-strength composites, which may combine low density and high strength and other outstanding capabilities in one kind of composites. Interface controlling and infiltration process totally determine the w
8、hole process of preparations of composites. The liquid magnesium 上海交通大学硕士学位论文 Vdoesnt wet the carbon fibers, which made it hardly to prepare the composites and reduce the capabilities of those finished ones. Now, the reported date of carbon fiber reinforced magnesium-matrix composites is still much
9、less than expected. And it is difficult to synthesize magnesium matrix composites because of the oxidization of magnesium. The infiltration kinetics of liquid magnesium into fibers was theoretically analyzed. The results showed that as for the unwetting system, the liquid infiltration could be possi
10、ble only when theoretical infiltration pressure which related with the surface tension of liquid metal, fiber volume fraction and the distribution of carbon fibers. And the process of infiltrating both between and inside the fiber bundles was discussed. According the analysis, two methods to solve t
11、he infiltration problem during the synthesis of carbon fiber reinforced magnesium-matrix composites was given, one is to coat the carbon fibers with a suitable film, and the other is to make a mixture of particle and carbon fibers preform. After removing the binder of the carbon fiber, a continuous,
12、 smooth SiO2 coating by sol-gel process, which improved the wet ability of carbon fibers and magnesium. The influences of water/silicon, ethanol/silicon, chemical addictive, coating speed, sinter process controlling, etc have been studied. The SiO2 coat have been investigated and analyzed by SEM、XRD
13、 ABSTRACT VIand Fourier Transform Infrared-Raman Spectroscope. Besides, micro sphere have been creatively hybridized in carbon fibers. Those unique global sharp enlarged the distances between fiber and fiber, which decreased the infiltration pressure when liquid magnesium filled into carbon fibers.
14、And mostly they dont cut the fibers to damage the fibers strength because of the spherical figuration. The infiltration processes of composites under a relatively low pressure have been realized with the help of SiO2 coating and micro sphere. The interface of magnesium and carbon fiber, the chemical
15、 reaction between the matrix and the coating have been investigated and analyzed by SEM, TEM, XRD. The mechanics and damping capacities of composites also have been tested. KEY WORDS: sol-gel process, mixture of particle and carbon fibers, infiltration, Carbon fiber reinforced magnesium-matrix compo
16、site 上海交通大学上海交通大学 学位论文原创性声明学位论文原创性声明 本人郑重声明：所呈交的学位论文，是本人在导师的指导下，独立进行研究工作所取得的成果。除文中已经注明引用的内容外，本论文不包含任何其他个人或集体已经发表或撰写过的作品成果。对本文的研究做出重要贡献的个人和集体，均已在文中以明确方式标明。本人完全意识到本声明的法律结果由本人承担。 学位论文作者签名：赵慧锋 日期：2007 年 2 月 2 日 上海交通大学上海交通大学 学位论文版权使用授权书学位论文版权使用授权书 本学位论文作者完全了解学校有关保留、使用学位论文的规定，同意学校保留并向国家有关部门或机构送交论文的复印件和电子版，允许论文被查阅和借阅。本人授权上海交通大学可以将本学位论文的全部或部分内容编入有关数据库进行检索，可以采用影印、缩印或扫描等复制手段保存和汇编本学位论文。 保密保密，在 年解密后适用本授权书。 本学位论文属于 不保密不保密。 （请在以上方框内打“”） 学位论文作者签名：赵慧锋 指导教师签名：王浩伟 日期：2007 年 2 月 2 日 日
