Controlling the location of carbon nanotubes (CNTs) within Al matrix is still challenging. To clarify the factors/mechanisms affecting the spatial distribution of CNTs, Short and Long CNTs were chosen as reinforcements, and their locations were characterized after ball milling, sintering and hot extrusion in order to study the effect of length-scale, thermal activation and external applied stress. The results showed that Long CNTs were only located at the grain boundaries (GBs). Differently, Short CNTs were mostly located at GBs when only external applied stress (ball milling) or thermal activation (sintering) is present, but entered grains with the synergy of thermal activation and external applied stress during thermomechanical process (hot extrusion). Based on the applied mathematical calculations, the main mechanism responsible for intragranular distribution of CNTs is the significant GB migration accelerated by thermal activation and external applied stress. The critical length for entering the CNTs in the grain interiors was calculated to be ∼103 nm, which agreed well with the experimental result (maximum length of ∼95 nm). The CNTs with the length larger than the critical value significantly decrease the velocities of themselves and GBs, and cannot be detached from GBs being still located at GBs in the Long CNT/Al composites.

控制铝基体中碳纳米管 (CNT) 的位置仍然具有挑战性。为了阐明影响碳纳米管空间分布的因素/机制，选择短碳纳米管和长碳纳米管作为增强材料，并在球磨、烧结和热挤压后对它们的位置进行表征，以研究长度尺度、热活化和外部效应的影响。施加的压力。结果表明，长碳纳米管仅位于晶界（GBs）。不同的是，当仅存在外部施加应力（球磨）或热活化（烧结）时，短碳纳米管主要位于GBs，但在热机械过程（热挤压）过程中通过热活化和外部施加应力的协同作用进入晶粒。基于所应用的数学计算，造成 CNT 晶内分布的主要机制是热活化和外部施加的应力加速了显着的 GB 迁移。计算出进入晶粒内部碳纳米管的临界长度为~103 nm，这与实验结果非常吻合（最大长度为~95 nm）。长度大于临界值的碳纳米管显着降低了其自身和GBs的速度，并且不能从仍然位于长CNT/Al复合材料中GBs的GBs上脱离。