旋转摩擦挤压粉末成形纯净石墨烯/铝基复合材料的界面演化与性能调控

将石墨烯，特别是蜂巢结构规整的纯净石墨烯复合到金属铝中可能大幅提高材料力学性能的同时使其功能性有突破，在许多领域有迷人的应用前景，但石墨烯难分散、与金属界面结合差，是制约复合材料应用的主要瓶颈。项目在前期研究的基础上，采用源自搅拌摩擦加工的旋转摩擦挤压粉末成形纯净石墨烯/铝基复合材料，依据合金化原子扩散的界面特性，提出扩散连接石墨烯与基体构筑界面过渡的新思路，明确扩散连接界面演化机制，把握影响石墨烯分散、结构保持与界面结构的关键因素，考察材料的力学和热性能，结合理论计算方法，诠释石墨烯对材料性能的影响机理，阐明界面结构与材料性能的关系，通过界面控制实现复合材料性能调控；同时，将其应用于高强铝合金，探索合金元素与石墨烯的相互作用机制，期望通过优化过程条件，发挥石墨烯与第二相的协同增强效应，最终有望获得一种同时优化复合材料力学性能和功能性的新途径，为此类复合材料的发展和应用提供理论和实验依据。

Owing to the extraordinary properties of ultra-high strength and modulus, high charge-carrier mobility with high thermal conductivity, graphene has proven to be an ideal reinforcement for metal matrix composite. Combining graphene, especially pristine graphene with perfect honeycomb lattice, into the aluminum matrix may greatly improve the mechanical properties of the composite and make a breakthrough in its functionality simultaneously, and therefore it has attractive application prospects in many fields. However, the excellent properties of graphene have far to be fully exploited in the practical graphene/aluminum matrix composite. Issues arised in the composite involve the poor dispersion of graphene in aluminum matrix and weak graphene/aluminum interface bonding. On the basis of previous research, the technology of powder rotary friction extrusion, which is derived from friction stir processing, is used to fabricate pristine graphene/aluminum matrix composite. According to the interface characteristics of alloying atom diffusion, a novel concept of constructing a graphene/aluminum transition interface by diffusion bonding is proposed for tailoring the interface microstructure and properties of the composite. The evolution mechanism of the diffusion bonding interface is clarified, and the key factors of tailoring the graphene dispersion, structure preserving and interface microstructure are obtained. The mechanical and thermal properties of the composite are investigated, and the influence mechanisms of graphene on the properties of the composite are interpreted by means of theoretical calculation. The intrinsic relationship between the interface microstructure and material properties is established. Moreover, the diffusion bonding interface is applied to high-strength aluminum alloy to explore the interaction mechanism between alloy elements and graphene, and the synergistic enhancement effect of graphene and second phase may be exerted by optimizing the process conditions. Finally, it is expected to obtain a novel way to optimize the mechanical properties and functionality of the composite at the same time, which will provide theoretical and experimental basis for the development and application of this kind of composite.