晶内分布碳纳米管增强铝基复合材料及其强化机制研究

针对碳纳米管/铝（CNTs/Al）复合材料中CNTs分布在Al晶界导致CNTs单一分散含量低与Al-CNTs界面结合差的问题，提出Al晶粒内部分布CNTs的新思路，即首先通过重复对高能球磨Al-CNTs粉末进行退火处理并添加过程控制剂，实现粉末扁平化-球化过程多次循环，促进CNTs分散并进入Al晶粒内部，随后采用低温烧结与大变形量热挤压实现高含量CNTs在基体晶内均匀分散与Al-CNTs有效界面结合。在此基础上，系统研究晶内增强型CNTs/Al复合材料的制备工艺与微观组织关系，揭示分散与成形过程中CNTs分布与尺寸、基体晶粒结构的演化规律，实现CNTs植入晶粒内部位置的可控设计，阐明晶内增强型CNTs/Al复合材料的变形行为与强化机制，为具有高强度、高模量、高塑性等优异力学性能Al基复合材料的制备及其在航空航天领域的应用提供理论支持与技术支撑。

Regarding the problems of low content of singly dispersed carbon nanotubes (CNTs) and poor bonding between Al and CNTs induced by the intergranular dispersion of CNTs in Al matrix composites, a new idea of intragranular distribution of CNTs is proposed. Firstly, the Al-CNTs composite powders after high energy ball milling are annealed and process control agents are added repeatedly to realize multiple cycles of the powder flattening-spheroidization process, which promotes the dispersion of CNTs into Al powders and grains. Then, low-temperature sintering and large-deformation hot extrusion are applied to realize the uniform dispersion of high-content CNTs in the matrix and effective Al-CNTs interface. On this basis, the relationship between the fabrication parameters and microstructure of intragranular-reinforcing typed CNTs/Al composites is systematically studied. The evolution of CNTs distribution, size and matrix grain features during dispersion and consolidation are revealed towards the controllable design of CNTs implantation positions in grains. The deformation behavior and strengthening mechanisms of intragranular reinforced CNTs/Al composites are clarified to provide theoretical and technical support for the preparation and aerospace applications of Al matrix composites with comprehensively excellent mechanical properties of high strength, high modulus and high plasticity.