熔铸法制备外加/自生双纳米相铝基复合材料及其协同强化机制

碳纳米管（CNTs）/铝复合材料具有优异综合性能，作为新一代飞行器零部件材料展现出巨大潜力，急需低成本规模化制备方法推广应用。熔铸法是其规模化制备的首选，然而由于CNTs在铝熔体中浮起团聚、难以被润湿、反应严重的问题导致熔铸制备难以实现。本项目提出CNTs表面镀铜解决熔铸难题、并使铜固溶析出纳米相进一步提高复合材料性能的新思路，即首先利用化学镀设计合成与铝熔体密度、界面匹配的纳米铜涂层/CNTs增强体，采用熔铸-时效工艺制备外加CNTs与原位自生纳米铝铜金属间化合物共增强的铝基复合材料。系统研究铜涂层的生长动力学机制与其对复合材料熔铸行为的影响，揭示铜-CNTs界面在熔铸与时效过程中的演变规律，探讨铝铜析出相位置、形貌与尺寸的控制方法，阐明双纳米相增强铝基复合材料的协同变形机理与强韧化机制。本项目完成后有望开辟熔铸制备高性能铝基复合材料的新方向，为其在航空航天领域的应用提供理论与技术支持。

Carbon nanotubes/aluminum (CNTs/Al) composites with excellent overall properties show great potential to be the material for the new-generation aircraft components. It is urgent to develop low-cost and large-scale preparation methods to promote their applications. Casting is the first choice, but difficult to realize because of the problems of floating-induced agglomeration, difficult wetting and serious reaction of CNTs in the Al melt. In this project, a new idea is put forward to solve the casting problems by plating copper (Cu) on CNTs and then controlling Cu to solute and precipitate as nanophases for further enhancing the properties of composites. Firstly, Cu nanofilms/CNTs reinforcements, which match with the density and interface between CNTs and Al melt, are designed and synthesized by electroless plating. Then, through casting and aging, aluminum matrix composites co-reinforced with ex-situ CNTs and in-situ Al2Cu nanophases are prepared. The growth kinetic of Cu films and their effect on casting behaviors of Al melt will be systematically investigated. The evolution mechanism of Cu-CNTs interface in the process of casting and aging will be studied. The controlling mechanism of the position and size of Al2Cu phase will be clarified. The synergistic deformation mechanism and strengthening/toughening mechanisms of ex-situ/in-situ dual nanophases in Al matrix composites will be explored. After the completion of this project, it is expected to open up a new direction of casting preparation of high-performance aluminum matrix composites, providing theoretical and technical support for their applications in the aerospace areas.