石墨烯增强铝基复合材料的仿生制备与界面行为研究

Employing the biomimetic composite configuating and interfacial behavior regulating, introducing the high-properties reinforcements into traditional metals to achieve their “lightweight, high strength/toughness, high modulus” has become an efficient way to develop the new-style structural materials, as well as the forefront and hot spot of metal matrix composites (MMCs) research. The present project attempts to fabricate the graphene/Al composites with three-dimensional nano “brick and mortar” structures. The surface consistent and uniform dispersion between the ultrahigh properties graphene and lightweight Al flakes will be focused, in order to achieve the biomimetic configuation design with the controllable content, interface regulated and strength/toughness matched. Based on microstructural characterization of prepared graphene/Al composites, the micropillars near graphene/Al interfaces are machined by Focused Ion Beam (FIB). Related nano-compression tests and crystal plasticity (CP) simulations are performed to study the deformation, slipping and strengthening mechanisms of graphene/Al interfaces in different aging state, interface morphology and composite scales. Macroscale tensile, bending tests and SEM, TEM in situ tensile tests of graphene/Al composites are carried out. Combined with the graphene/Al interfacial behavior, the multiscale modeling and properties prediction of the graphene/Al composites are conducted to reveal the strengthening/toughening mechanisms bewteen the biomimetic configuation, interfacial behavior and structure- properties relationship in graphene/Al composites.

采用仿生构型设计与界面行为调控，引入高性能增强相以使传统金属实现“轻质、高强韧、高模量”是发展新型结构材料的有效手段，也成为金属基复合材料研究领域的前沿与热点。本项目拟将超高力学性能石墨烯与典型轻质金属Al片通过仿生复合化，重点解决石墨烯与金属Al片的表面相容与均匀分散问题，实现含量可控、界面调控及强韧匹配的构型设计，制备具有三维纳米“砖砌”结构石墨烯/Al复合材料。依据所制备石墨烯/Al复合材料的显微组织特征，采用聚焦离子束（FIB）微加工石墨烯/Al界面的Micropillars，结合纳米压缩试验与晶体塑性模拟研究石墨烯/Al界面在不同时效状态、界面形貌及复合尺度下的变形、滑移及强韧机制。通过引入界面性能的石墨烯/Al复合材料多尺度建模与性能拟实，结合复合材料的宏观拉伸、弯曲及SEM、TEM原位拉伸试验，研究石墨烯/Al复合材料的仿生构型、界面行为与构-效关系间耦合强韧化机理。

复合化是金属材料实现高性能化的有效途径之一，传统的金属基复合材料多以增强相与结构的空间均匀分布为特征，未过多地考虑复合构型效应，难以极大发挥组分间的协同、耦合和交叉响应。目前，新型纳米材料、仿生构型设计与复合界面调控是金属基复合材料创新发展的典型要素，通过三者有机结合与协同是研发新型金属基复合材料的重要手段与研究热点。通过将高性能石墨烯与轻质金属Al片通过叠片冶金相复合，本项目研究了仿生制备、界面行为与构效关系三方面难题，完成了申请计划的研究内容。通过球磨工艺调控与材料表面改性，解决了石墨烯与金属Al片的均匀分散难题；通过热压烧结与轧制结合，制备出了仿生构型石墨烯/Al复合材料；针对不同含量石墨烯/Al复合材料，开展了单轴拉伸、三点弯曲及原位拉伸等材料试验测试。采用聚焦离子束（FIB）加工出多种包含石墨烯/Al界面的复合微柱，揭示了石墨烯含量与取向、复合微柱尺寸效应、微柱压缩应变率等对微柱压缩性能的影响规律；通过有限元模拟并结合实验验证，揭示了石墨烯/Al界面在不同界面状态及复合尺度下的界面强度与强韧机制。基于统计分析与几何建模，建立了可有效重构石墨烯种类、尺寸、含量、形貌及取向等可控分布的结构模型；引入了弹塑性、损伤及断裂等力学行为，开展了石墨烯/Al复合材料的多种力学变形模拟，揭示了体积含量、界面强度及复合构型等对石墨烯/铝复合材料的宏观响应。当前结合材料基因工程与数据挖掘技术，本项目系统构筑了一个从材料制备、到组织表征、到界面调控、再到构效关系的石墨烯/Al复合材料基础研究平台，揭示了仿生构型、界面行为与构效关系间的耦合响应规律，为金属材料的仿生设计与复合制备提供了理论依据。今后将以单向石墨烯/Al复合材料为复合基元，逐步向如梯度、交错等构筑复合材料发展，拓宽材料、力学与计算等多学科交叉的金属基复合材料研制新方法。