碳纳米管包覆氧化镁增强镁基复合材料界面调控及强韧化机制

Carbon nanotubes (CNTs) is the excellent reinforcement of magnesium based composit due to it’s fantastic mechanical properties, such as high strength and high elastic modulus. The keypoint is how to obtain the well-devisified CNTs with good interface bonding in the Matrix. CNTs will be coated with MgO by suitable process, which could effective disperse the CNTs in the Mg matrix by the medium of MgO acting as potent heterogeneous nucleation sites for α-Mg phase, since the interface of MgO/α-Mg is semicoherent with small crystallographic misfit. This novel idea could realize the combination of effective dispersion of CNTs with the grain refinement of the α-Mg matrix, then improve 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 by CNTs coating with MgO. The interface behavior of this composite will be focused by analysis the interface structure, bonding strength and failure mechanism of interfaces among CNTs/MgO/α-Mg, which will further be used to adjust the interface. The strenghening mechanism of Mg based composite with CNTs will be studied. The theoretical model of elastic modulus of Mg based composite with CNTs will be constructed. This project has significant scientific meaning for the development and design theory of Mg based composite with high performance and promotes its application.

碳纳米管具有优异的力学性能(高强度和高弹性模量)，是镁基复合材料优良的增强体。如何提高碳纳米管在镁基体中的分散性和界面结合，是镁基复合材料研究的关键科学问题。合理利用氧化镁与镁基体良好的晶体取向关系(半共格界面)，对碳纳米管进行包覆氧化镁表面处理，借助氧化镁作为形核载体，把碳纳米管分散在镁晶体核心，巧妙地实现碳纳米管的有效分散和良好界面结合，同时获得晶粒细化，进而改善镁基复合材料综合力学性能。.本项目研究碳纳米管包覆氧化镁增强镁基复合材料的界面、显微结构、力学性能以及断裂特征的相互关系；研究碳纳米管/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，对其界面进行调控；研究碳纳米管增强镁基复合材料的强韧化机制，建立碳纳米管增强镁基复合材料弹性模量的理论模型。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。

针对氧化镁改善碳纳米管（MgO@CNTs）增强镁基复合材料，对其界面特性和力学行为展开研究。研究内容包括碳纳米管包覆氧化镁增强镁基复合材料的制备工艺；氧化镁/镁基体/碳纳米管之间的界面特性；碳纳米管包覆氧化镁增强镁基复合材料的强化机制；碳纳米管包覆氧化镁增强镁基复合材料的弹性模量预测模型，以及碳纳米管包覆氧化镁增强镁基复合材料的工艺-组织结构-力学性能之间的关联模型。本项目对氧化镁改善碳纳米管（MgO@CNTs）增强镁基复合材料的界面行为和力学性能进行了深入的探讨，项目期间共发表SCI论文11篇，中文核心1篇，授权发明专利3项，在申请发明专利1项，培养研究生12名。项目期间取得的成果对我国镁基复合材料的制备技术提升具有重要意义，为未来高性能镁基复合材料的研究趋势提供了可行的理论依据，具有重要的学术意义。此外，项目期间培养了众多学术人才，向镁合金行业的研究和应用领域输送新鲜血液。