高强韧CNTs/Al复合材料仿生构型设计与制备基础研究

Natural evolution with thousands of years created a shell possessed the perfect micro-nano lamellar structure, which results in the shell exhibiting the best combination of strength and toughness. Inspired by that, the applicant team proposes a novel fabrication method for bionic micro-nano lamellar structure CNTs/Al composites by combining the electrophoretic deposition, spark plasma sintering and accumulative roll bonding. This proposal can solve the inverse relationship between strength and toughness of Al matrix composites through control the lamellar structure and taking advantage of the lamellar structure effect. Besides, this method can solve the common problems of carbon nanotubes cluster and the control of interface reaction, too. The applicant team will optimize fabrication craft and study on the construction and regulation mechanism of lamellar structure. The effects of the structure parameters on the microstructure and mechanical properties of CNTs/Al composites will be studied. Finally, during the extension process, the local strain distribution and microstructure evolution will be researched by the in-situ tensile with digital image correlation and electron microscope technology, and the crack initiation and propagation behavior will be in-situ researched by three-dimensional tomography technology. Based on above study, the applicant team will reveal the lamellar structure effects and the strengthening and toughening mechanism of CNTs/Al composites. This research will also provide a theoretic basis and experimental data for the design and fabrication of metal matrix composites.

千百年的自然进化，造就了贝壳的完美微纳米层状结构，致使其强度-韧性达到最佳匹配。受此启发，本项目创新性地结合电泳沉积、放电等离子烧结与室温叠轧等技术，提出一种仿生微纳米层状CNTs/Al复合材料的新型制备方法，通过调控复合材料的微纳米层状结构，充分发挥其强化与韧化双重效应，解决铝基复合材料的强度-韧性倒置的瓶颈问题，同时解决CNTs易团聚，界面反应难控制等共性问题。优化制备工艺，阐明仿生层状结构的构建与调控机理；探明层状结构参数对CNTs/Al复合材料显微组织和力学性能的影响规律；结合SEM与数字图像关联技术原位研究CNTs/Al复合材料在拉伸变形过程中局部应变分布与演化规律；利用三维断层成像技术原位研究微纳米层状CNTs/Al复合材料在拉伸过程中的裂纹萌生与扩展行为；揭示微纳米层状CNTs/Al复合材料的结构效应与强韧化机理，为新型铝基复合材料的设计及制备提供理论基础与试验依据。

本项目通过模仿贝壳结构设计微纳米层状碳纳米管(CNTs)增强铝基复合材料(CNTs/Al复合材料)，利用CNTs超强的力学性能和微纳米层状结构优异的结构效应，研发高强韧性的铝基复合材料。研究团队研发了一种CNTs分散均匀界面反应可控的新型制备技术，构建微纳米层状CNTs/Al复合材料，并研究CNTs分散规律，调控复合材料的层状结构，阐明该复合材料的层状结构效应与强韧化机理，解决复合材料强度-韧性的倒置矛盾，为新型纳米相增强铝基复合材料的设计和制备提供理论基础与试验依据。此外，在国家双碳战略背景下，轻量化已成为现代装备制造业的迫切需求。本项目研发制备成功的层状碳纳米管(CNTs)增强铝基复合材料具有优异的比强度和力学性能，使其在航天、航空和汽车等领域具有广泛的应用前景。