High strength and high electrical conductivity in copper reinforced with intra-/inter-granular graphene in-situ exfoliated from graphite

How to overcome strength-electrical conductivity trade-off is essential for functional and structural applications of Cu matrix composites. Here we propose a new dispersion and strengthening strategy to prepare graphene/Cu matrix composites. The graphene reinforcements are in situ exfoliated from graphite flakes through plasma assisted ball milling, and are intra-/inter-granularly dispersed in the Cu matrix after hot-rolling process. The graphene/Cu matrix composite has high tensile strength up to ∼497 MPa and electrical conductivity of 84.2% IACS, contributed by intra-/inter-granular graphene with average size of about 22 nm and 132 nm, respectively. In-situ electron microscopy and molecular dynamic simulation are performed to investigate deformation behavior of the composites, revealing that interaction between intra-/inter-granular graphene and dislocations effectively increase dislocation storage ability. This work offers a general pathway for fabricating graphene/Cu matrix composite with well-balanced strength and electrical conductivity.