碳纳米管纤维在空间环境下的力学行为演变规律研究

The rapid development of aerospace science and technology requires the developing and manufacturing of advanced materials with superior performances. However, the present aerospace materials such as metals and carbon fiber composites are still weak in durability and lack of functionality, strongly limiting their space applications. Owing to the superior properties of light weight, high strength, and electrically and thermally conducting, carbon nanotubes (CNTs) can exhibit broad application prospects in extreme environments, and provide new material support for future development of space technology.. In this proposal, by focusing on the assembly material of CNTs, CNT fiber, we will investigate its structural transformation and the evolution of mechanical properties at extreme space environments, such as vacuum, atomic oxygen, irradiation, and high/low temperatures, in order to find out the adaptability in space applications. At the same time, by combining the micro/nano structural characterizations and theoretical and computational simulations, we will reveal and understand the evolution mechanism. Upon the deep learning of the strengthening and failure mechanisms at extreme conditions, and the optimizing of fiber structure, we will also develop the technique to modulate the mechanical performances under the synergistic effect of various space parameters. The execution of this project can provide important scientific support for the material selection, structural design and optimization, and potential application for future high-performance multifunctional aerospace materials.

随着我国航天科技的快速发展，空天科学技术将成为未来10年的国家战略，然而目前传统航天用金属材料和碳纤维复合材料在耐用性和多功能性方面受到限制。碳纳米管因具有轻质、高强度、高导电、高导热等优异特性被认为是一种在空间环境中具有广阔前景的纳米材料，为未来空间材料的发展提供了新的契机。本项目拟以探索碳纳米管纤维在空间环境中的适应性为研究目标，开展典型空间极端环境如真空、原子氧、辐照、高低温下的结构转变特性和力学性能，并揭示力学行为的演变规律。同时采用微纳结构表征手段结合理论计算建模更直观的对相关条件下的行为进行模拟，深入认识空间极端环境下碳管纤维的力学增强或失效机理，在此基础上进一步优化结构设计，研究碳纳米管纤维在空间多因素协同作用下的力学行为。以期为未来碳纳米管纤维在空间环境中高性能多功能材料的选材、优化设计等提供详实可靠的科学依据。

碳纳米管纤维是由碳纳米管组装而成的一维线性材料，具有优异的轻质和力、电、热综合性能，在航空航天等极端环境下有极大的潜在应用。本项目以碳纳米管纤维为研究对象，从碳纳米管纤维的力学增强及多功能特性出发，首先通过后牵伸提高碳纳米管的取向，将纤维的拉伸强度提高到2.0GPa以上，进而通过析氢膨胀网络重构牵伸复合将纤维的力学性能提高到4GPa以上；在纤维增强的基础上，进而研究了多股纤维并合、纤维复合材料、纤维复合纱线等更为宏观尺度的力学性能，同时也研究了碳管纤维与树脂的界面特性、打结特性、高低温耐受性等；为了进一步拓宽碳纳米管纤维的多功能特性，将碳纳米管纤维与相变材料复合，利用碳纳米管特有的网络骨架结构得到了力、电、热及相变潜热性能优异的相变复合纤维；在空间环境的适应性方面，主要研究了碳纳米管纤维在热真空、原子氧、高低温环境下的力学失效情况，实验发现纤维经过热真空和高低温循力学基本可以维持原纤维的水平，随着热循环次数增加对力学略有下降趋势，随着原子氧处理时间的增加纤维的力学性能呈下降趋势，分析主要与碳管纤维微米级尺寸有关，原子氧刻蚀深度也是微米级，制备成碳管纤维复合材料将大大缓解。本课题的研究为碳纳米管纤维在空间环境中高性能多功能材料的选材、优化设计等提供了实验依据，有望推动碳纳米管纤维在空天领域的应用。