Nucleation and growth mechanisms of interfacial carbide in graphene nanosheet/Al composites

Abstract

The interface reaction is the focus of interface control in the graphene/Al composites, but its evolution processes are still unclear. The present work revealed the nucleation and growth mechanisms of the interfacial reaction product, aluminum carbide (Al4C3), in the graphene nanosheet (GNS)/Al composites. The nucleation of Al4C3 was found to mainly start at the open edge of GNSs due to the high chemical reactivity, and the formed Al4C3 was found to mostly locate either along or at an angle to the Al grain boundary, e.g. (i) ∼25° angle between Al4C3 (003) and Al (-111); (ii) Al4C3 (003)//Al (1-11); (iii) Al4C3 (003)//Al (002); (iv) Al4C3 (003)//Al (2-20). The growth of Al4C3 was controlled by the diffusional growth parallel to (003) plane and the nucleation growth perpendicular to (003) plane. Besides, the possible intermediate states, the C–Al interfacial transition zone, and the interfacial reaction transition phase were also observed. This work provides a theoretical basis for the further tailoring of interface bonding and property improvements of graphene/Al composites.