▎ 摘　　要

Dislocation strengthening plays a constructive role in exploring the improvement of mechanical properties of deformed aluminum matrix composites. However, theories about the interaction of different reinforcers and special structures on dislocations are still in their infancy. Here we prepare a high strength-toughness nanolaminated AA6111 matrix composite synergistically reinforced with graphene nanoplates (GNPs) and in situ ZrB2 nanoparticles. The microstructure and dislocation configurations of the composites are characterized by transmission electron microscopy (TEM) to investigate the influence of GNPs and ZrB2 nanoparticles on the initiation, motion, and annihilation of dislocations. It is found that the dislocations are confined within the elongated grains by the sandwich nanolaminated structure formed by GNPs and aluminum. The dislocation motion shift from a graphene-free grain boundary crossing mechanism to a confined layer slip (CLS) mechanism, increasing the intragranular dislocation density. The dispersed particles transform the dislocation pile-up mechanism into a dislocation pinning network mechanism. We estimate the contribution of dislocation strengthening to the strength of composites. The results demonstrate that the shear stress of the grain region on the side with ZrB2 particles near GNPs are significantly higher than that on the other side without particles, forming a spaced arrangement special structure of soft grains and hard grains. This work unveils a strategy to improve nanolaminated AMCs by employing zero-dimensional and two-dimensional reinforcements through dislocations strengthening.