Synergistic strengthening and toughening of copper coated graphene nanoplates and in situ nanoparticles reinforced AA6111 composites

Abstract This paper aims to investigate the synergistic effect between graphene nanoplates (GNPs) and in stiu nanoparticles, strengthening mechanism and toughening mechanism for aluminum matrix composites. The copper coated graphene nanoplates (Cu-GNPs) and in situ ZrB2 nanoparticles synergy reinforced AA6111 matrix composites were prepared with the help of semi-solid stirring casting technology and the hot rolling deformation. The microstructure characterization shows that the Cu-GNPs could keep their integrity well and inhibit the severe harmful interfacial reaction lying on the grain boundaries. Both GNPs and ZrB2 nanoparticles have tight bonding interfaces with aluminum. The synergistic effect between GNPs and nanoparticles plays an important role in the process of rolling deformation, where GNPs can promote particle dispersion, and particles can reduce the stress concentration generated at the edges of GNPs. Furthermore, the effects of GNPs and in stiu nanoparticles were evaluated by analyzing the strengthening mechanism and the toughening mechanism. Finally, the GNPs+ZrB2/AA6111 composites with 0.1 wt% GNPs and 3 wt% ZrB2 achieved a positive balance that a high ultimate tensile strength as 426 MPa, 33.5% higher than that of AA6111 and keep an elongation greater than 15%.