原位还原石墨烯增强镁基复合材料的界面行为和强韧化机制

Graphene is the excellent reinforcement of magnesium based composite due to its fantastic mechanical properties. The key point is how to uniform disperse the high content single-/few-layered graphene with good interfacial bonding in the matrix. A homogeneous distribution of graphene in the matrix has been successfully obtained through in-situ reduction of graphene oxide (RGO) by sintering process after the graphene oxide (GO) was uniformly dispersed in the Mg matrix [GO+Mg→RGO+MgO]. Because GO can be easily exfoliated into the single-/few-layered nanosheets by ultrasonication, which is beneficial to the final dispersion of graphene. In addition, the in-situ RGO reveals a strong interfacial bonding with the surrounding matrix by the medium of MgO acting as the potent heterogeneous nucleation sites for α-Mg phase because of the interface of MgO/α-Mg is semi-coherent with small crystallographic misfit. This novel idea could realize the combination of effective dispersion of graphene possess good interfacial bonding and grain refinement of the α-Mg matrix, and then improving the mechanical properties of Mg-based composite..This project will study the relationships among interface, microstructure, mechanical properties and fracture feature of Mg-based composite with graphene. The interface behavior of this composite will be focused by analysis the structure, bonding strength and failure mechanism of interfaces among RGO/MgO/α-Mg. The strengthening mechanism of graphene-Mg nanocomposite with will be studied. The theoretical model of the Mg-based composite will be constructed. This project has significant meaning for the development and design theory of Mg-based composite with high performance and promotes its application..

石墨烯具有优异的力学性能，是镁基复合材料优良的增强体。如何在镁基体中添加单层、少层含量高且分散均匀的石墨烯并提高界面结合，是镁基复合材料研究的关键科学问题。利用氧化石墨烯(GO)含有丰富的含氧官能团而容易超声剥离、分散形成高含量单层、少层GO的特性，在镁基体中形成均匀分散，通过原位还原反应GO+Mg→RGO(石墨烯)+MgO(界面产物)，巧妙地实现了高含量单层、少层石墨烯的有效分散和良好界面结合(半共格界面)，同时获得晶粒细化(MgO异质形核)，进而改善复合材料的综合力学性能。.本项目研究石墨烯/镁基复合材料的界面、微结构、力学性能及断裂特征的相互关系；研究石墨烯/氧化镁/镁基体间的界面结构、界面结合强度及界面失效机制；研究石墨烯/镁基复合材料的强韧化机制并建立关系模型。本项目研究成功，将推动高性能镁基复合材料设计理论的发展，开拓一条制备镁基复合材料的新途径，具有重要的学术意义和应用前景。

石墨烯具有优异的力学性能，是镁基复合材料优良的增强体。如何在镁基体中添加单层、少层含量高且分散均匀的石墨烯并提高界面结合，是镁基复合材料研究的关键科学问题。本项目利用氧化石墨烯(GO)优异的分散特性，在镁基体中引入单层、少层含量高且分散均匀的GO，通过原位还原反应GO+Mg→RGO(还原石墨烯)+MgO(界面产物)，巧妙地实现了高含量单层、少层石墨烯在镁基体中的均匀分散。TEM、SEM、力学性能测试等表征分析发现：石墨烯在镁基体中分散均匀，界面产物MgO与镁基体形成了半共格界面结合，有效提高了石墨烯与镁基体的界面结合质量；同时细化了镁基体组织(MgO异质形核)，复合材料的综合力学性能提高显著。本项目阐明了石墨烯/氧化镁/镁基体之间的界面结构、界面结合强度及界面失效机制，揭示了石墨烯/镁基复合材料的强韧化机制，推动了高性能镁基复合材料设计理论的发展，具有重要的学术意义和应用前景。.项目研究成果发表论文14篇，其中SCI论文9篇（含高引论文Carbon,127 (2018),177-186），EI论文2篇，中文核心2篇；授权国家发明专利3项；获中国科技产业化促进协会科技创新二等奖1项，获江西省自然科学三等奖1项。