石墨烯增强铝基复合材料的制备及力学性能研究

发布时间：2018-05-27 02:22

本文选题：石墨烯 + 铝基复合材料　；参考：《哈尔滨理工大学》2015年硕士论文

【摘要】：石墨烯因其具有非常优异的物理性能和机械性能，被认为是最理想的金属基复合材料增强体。然而石墨烯在金属基体中非常容易发生团聚，已成为制约石墨烯增强金属基复合材料发展的关键因素。因此寻求一种新的制备技术是发展石墨烯增强金属基复合材料的关键。本文首先采用Hummers制备含有大量负电荷的氧化石墨烯(grapheneoxide,GO)，然后使用阳离子表面活性剂处理铝粉使其表面带有正电荷，并以静电自组装的方式将氧化石墨烯均匀的吸附在铝粉表面。最后采用热压烧结的方法制备了石墨烯增强铝基复合材料。利用金相显微镜、X射线衍射和扫描电镜等方法研究了石墨烯在复合材料中的分散情况和不同活性剂使用量和石墨烯添加量对复合材料的组织，结构和性能的影响。 Hummers法对原始石墨进行了有效的剥离，制得的氧化石墨烯层数较少。并且氧化石墨烯上存在大量的含氧基团，，使得氧化石墨烯带有很强的负电荷。将其与表面处理后带正电的铝粉通过静电自组装混合后，氧化石墨烯可以均匀的吸附在铝粉表面，且没有明显的团聚现象发生，实现了石墨烯的均匀分散。表面活性剂的使用量对复合材料的组织和力学性能的影响非常显著，当活性剂用量为5wt.%时，热压烧结过程中会有大量的活性剂残留在铝粉颗粒边界处，形成较厚的碳层，使铝粉之间的烧结性能下降，相比于活性剂使用量为1wt.%时其抗拉强度降低了50%，但是硬度略有提高。复合材料的硬度和抗拉强度随着石墨烯的含量增加，呈现出先增加后减少的趋势，石墨烯的添加量为0.3wt.%时其力学性能达到最佳，相比于纯铝其抗拉强度提高了22%，硬度提高了30%。随着石墨烯含量的增加，复合材料的断口形貌主要表现出脆性断裂和韧性断裂相结合的特征，其延伸率持续下降，石墨烯主要分布在复合材料的界面处，呈现出明显的拔出和断裂状态。
[Abstract]:Because of its excellent physical and mechanical properties, graphene is considered to be the most ideal metal matrix composite reinforcement. However, graphene is easy to agglomerate in metal matrix, which has become a key factor restricting the development of graphene reinforced metal matrix composites. Therefore, to seek a new preparation technology is the key to develop graphene reinforced metal matrix composites. In this paper, graphene oxide (graphene oxide) with a large amount of negative charge was prepared by Hummers, then the surface of aluminum powder was treated with cationic surfactant to make the surface of aluminum powder positively charged, and graphene oxide was uniformly adsorbed on the surface of aluminum powder by electrostatic self-assembly. Finally, graphene reinforced aluminum matrix composites were prepared by hot pressing sintering. The dispersion of graphene in the composites and the effects of the amount of active agents and graphene on the microstructure, structure and properties of the composites were studied by means of X-ray diffraction and scanning electron microscopy. Hummers method was used to exfoliate the original graphite effectively and the number of graphene oxide layers was less. And there are a lot of oxygen groups on graphene oxide, which makes graphene oxide have strong negative charge. After mixed with the surface treated aluminum powder with positive charge through electrostatic self-assembly, graphene oxide can be uniformly adsorbed on the surface of aluminum powder, and there is no obvious agglomeration, which realizes the homogeneous dispersion of graphene. The amount of surfactant has a significant effect on the microstructure and mechanical properties of the composites. When the amount of surfactant is 5 wt.%, a large number of active agents will remain at the boundary of aluminum particles in the hot pressing sintering process, forming a thick carbon layer. The sintered properties of aluminum powder were decreased by 50% compared with that of 1 wt.% of active agent, but the hardness was slightly increased. The hardness and tensile strength of the composites increased firstly and then decreased with the increase of graphene content. The mechanical properties of the composites reached the best when the content of graphene was 0.3 wt.%, and the tensile strength and hardness increased 22% and 30% respectively compared with pure aluminum. With the increase of graphene content, the fracture morphology of the composite mainly shows the characteristics of brittle fracture and ductile fracture, and its elongation continues to decrease, and graphene mainly distributes at the interface of the composite. There are obvious pullout and fracture states.
【学位授予单位】：哈尔滨理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33

【参考文献】