碳纳米相三维网络增强金属基复合材料的力学性能与界面结构

For the traditional metal matrix composites (MMCs) reinforced by particles or fibers, the inverse relationship between strength and toughness has become a bottleneck to their development and application. The key to solve the problem is to develop novel types and structures of reinforcement, as well as new composite techniques. In this project, with the purpose of increasing both strength and ductility of MMCs at same time, 3D network-like carbon nanomaterials (nanotubes and graphene) reinforced MMCs will be designed and fabricated through the combination of in-situ chemical vapor deposition and powder metallurgy. The in-situ synthesis condition and the structure parameters (content, morphology and spatal structure) of carbon nanotube and graphene, as well as the microstructure of matrix, will be regulated, and the synergy effect on the “Reinforcement Structure - Boundary Structure - Mechanical Properties” of MMCs will be studied. In combination with theoretical calculations, the strengthening and toughening mechanism of 3D network-like structure reinforced MMCs will be investigated, the action behavior of the interface structure on the mechanical properties will be explored, and thus, the ‘Interface Structure－Mechanical Properties’ relation model is expected to be established. The structure evolution and performance changes during processing (deformation, heat treatment and etc.) will be studied, in order to reveal the dependencies of Preparation Process－Microstructure－Performance and to obtain the way to regulate the mechanical properties of the composite materials. Through this project, the scientific basis, design strategy, and preparing techniques for developing new high-performance MMCs are expected to be provided.

传统上以颗粒或纤维为增强体的金属基复合材料（MMCs）在提高强度的同时往往会带来韧性的降低，该强度-韧性的倒置关系是制约其发展的瓶颈。研发新的增强体和增强结构及其复合技术，是破解这一难题的关键。本项目以制备高品质碳纳米材料（碳纳米管和石墨烯）构筑的三维网络增强MMCs，同时实现其增强和增韧为目标，将原位化学气相沉积法与粉末冶金法相结合，通过对碳纳米管和石墨烯在金属基体上的原位合成条件、结构参数（含量、形貌、空间结构）和基体微观组织的调控，研究复合材料“增强相结构－界面状态－力学性能”之间的协同耦合效应；结合理论计算，研究三维网络增强MMCs的强韧化机理，探明界面结构对性能的作用机制，建立界面结构-力学性能关系模型；研究复合材料在加工过程(变形、热处理等)中的结构演变和性能，揭示工艺-组织-性能的依存关系，获得对力学性能的调控途径。为发展新一代高性能MMCs提供科学依据、设计策略和制备技术。

随着高新技术发展对高强高韧金属材料的需求日益增加，传统的合金及其复合材料难以有效解决强度-韧性倒置的瓶颈问题，亟需发展新制备方法并设计具有全新增强体空间构型的金属基复合材料。该课题在金属基体（铜、铝）中利用原位生长的方法，设计合成了碳纳米相（石墨烯和碳纳米管）呈三维网络空间构型的复合材料，发展了原位合成非连续和连续三维石墨烯增强铜基复合材料的新方法，深入分析了其合成机理、石墨烯/铜的特殊组织结构的形成机制；研究了影响非连续和连续三维石墨烯网络增强铜基复合材料力学性能的关键因素，通过优化石墨烯的含量和复合材料组织调控，实现了强度和塑韧性、导电导热性能同时提高，揭示了网络构型下复合材料组织对性能的作用规律；开发了制备碳纳米管/铝致密材料和碳纳米管/泡沫铝的全新工艺，明晰了碳纳米管含量对增强泡沫铝材料的室温和高温压缩性能、高速冲击性能以及阻尼性能的影响规律；系统研究了网络构型碳纳米相增强金属基复合材料的强韧化机制，特别是对三维连续石墨烯网络的外在增韧机制进行了深入分析，揭示了网络构型由于增强相连续化所具有的特殊韧化机制。此外对原位生长的碳纳米相/金属界面演化机制及其对力学性能的微观作用规律进行了深入分析，明确了石墨烯的表面金属颗粒修饰对复合材料界面结构、组织和力学行为影响的内在机制。通过上述研究，获得了增强相分散良好、结构保持完整、界面结合优良、结构连通的碳纳米相增强金属基复合材料，为下一步发展高性能金属基复合材料提供了重要的理论基础和实验依据。