Fabrication of three-dimensional graphene/Cu composite by in-situ CVD and its strengthening mechanism

In this study, a Cu matrix composite is synthesized reinforced by an in-situ three-dimensional graphene network (3D-GN) grown through chemical vapor deposition (CVD). Nano Cu powders and polymethylmethacrylate (PMMA) are employed as matrix and carbon source respectively. PMMA is dispersed on Cu powders after ball-milling. During the CVD process, carbon atoms from pyrolyzed PMMA diffuse and precipitate on Cu powders. By inheriting the morphology of Cu powders, carbon atoms build a 3D-GN in-situ on Cu powders. A bulk 3D graphene/composite with 0.5 wt% graphene is obtained by vacuum hot-press sintering. The favorable interfaces that crucial to the achievement of exceptional mechanical properties of a bulk composite are verified by TEM and SEM characterizations. A yield strength and tensile strength of 290 MPa and 308 MPa respectively are achieved of the composite. The structure of 3D-GN is well preserved in the bulk composite. We demonstrate that the 3D-GN serves as an effective obstacle to the propagation of dislocations by TEM further.