石墨烯增强镁基复合材料的制备及性能研究

发布时间：2018-04-08 07:47

  本文选题：石墨烯　切入点：镁基复合材料　出处：《沈阳理工大学》2017年硕士论文

【摘要】：石墨烯具有优越的物理性能和机械性能,近年来被广泛以增强体形式应用到聚合物基、陶瓷基和金属基复合材料中。然而,少有文献记载人们对石墨烯增强镁基复合材料的研究,因此设计进行了石墨烯增强镁基复合材料的相关实验研究。首先,通过改进的Hummers法制备了单层或少层石墨烯,采用化学镀铜法制备了镀铜石墨烯。然后,采用球磨混料+冷压+热压烧结工艺制备了石墨烯增强镁基复合材料,利用金相显微镜、X射线衍射仪和扫描电镜等检测手段对材料的组织和成分进行表征和分析,并用维氏硬度计对它的硬度进行测试。最后,通过CASTEP第一性原理计算软件对石墨烯-金属复合界面进行计算,研究了不同界面的性能和结合强度。烧结温度达到595℃时,制得的复合材料表面能够保持清洁无裂纹,复合材料内部结合紧密,不容易发生溃散。1wt.%石墨烯能够对镁晶粒形成很好的包覆,在制得的复合材料内部晶界处石墨烯呈连续网状分布,而石墨烯的添加量超过1wt.%时,过量的石墨烯容易在复合材料内部产生团聚,从而对复合材料的组织等因素产生不利影响。该石墨烯含量下的复合材料硬度能够达到50HV,比铸态和冷加工状态下的纯镁分别提高了66.7%和38.9%。当混料时间达到12h时,复合材料的组织均匀性即可达到最大,持续增加混料时间,对组织均匀性改善的意义不明显。通过轧制及热处理,复合材料的组织能够得到细化,而且随着热处理时间延长至3h,复合材料的组织均匀性得到改善。界面处石墨烯与铜基体存在强烈的相互作用,界面结合能达到4.79J·m-2,属于化学结合,而石墨烯与铝和镁基体之间的相互作用较弱,界面结合能分别为1.415J·m-2和0.52J·m-2,属于物理结合。通过对石墨烯表面镀铜能够改善石墨烯与镁基体之间的润湿性,使复合材料内部的界面结合得到增强。
[Abstract]:Graphene has been widely used in polymer, ceramic and metal matrix composites in recent years because of its excellent physical and mechanical properties.However, there are few studies on graphene reinforced magnesium matrix composites, so some experimental studies on graphene reinforced magnesium matrix composites have been carried out.Firstly, monolayer or less layer graphene was prepared by modified Hummers method, and copper-coated graphene was prepared by electroless copper plating.Then, graphene reinforced magnesium matrix composites were prepared by cold pressing and hot pressing sintering process. The microstructure and composition of the composites were characterized and analyzed by means of metallographic microscope X-ray diffraction and scanning electron microscopy.Its hardness was tested by Vickers hardness meter.Finally, the graphene / metal composite interface was calculated by CASTEP first-principle calculation software, and the properties and bonding strength of different interfaces were studied.When the sintering temperature reaches 595 鈩，

本文编号：1720703