Strengthening behaviour of continuous graphene network in metal matrix composites

Abstract

This study provides an insight into the structure-property relationship of graphene network (GN) reinforced metal matrix composites (MMCs). Molecular dynamics results show that the interlocking structure improves the deformation compatibility between the GN and matrix, as well as increases the load-sharing of GN. And the mechanical interlocking can be further enhanced by the dislocation-GN interactions as the GN being straightened. The straightening of GN also enables itself to release its stress concentrations through overall deformation, which helps the GN perform better in dislocation-blocking than graphene sheets. Besides, curved portions of GN contribute more to dislocation-GN interactions while the straight portions do better in load-sharing. With the hole-like defects on whether straight or curved portions of GN, both the strength and Young's modulus of the imperfect GN reinforced composites are reduced. However, these defects enable the matrix to be connected into a continuous body, by which the ductility of imperfect GN reinforced Ni matrix composites is improved since their failures are mainly dictated by the fracture of Ni matrix, while the rupture of GN determines the failure of composites reinforced by the GN without hole-like defects.