Direct Consolidation of Copper–Graphene Composite by Rotary Swaging

Improving the mechanical properties of copper and graphene composites is of a high interest. In accordance with the Hall–Petch law, the finer the grains, the higher the strength of material. Direct consolidation of fine powders is thus highly promising for preparation of (ultra)fine‐grained copper composites featuring more or less homogeneous distributions of graphene particles. This study is original as it investigates the feasibility of using the industrially applicable intensive plastic deformation method of rotary swaging for direct consolidation of copper–graphene composites featuring enhanced performance. The results show that the swaging ratio of 1.4 results in a satisfactory consolidation of the powders. However, the final consolidated piece swages with the swaging ratio of 2.8 features a relatively high microhardness of 108.2 HV0.05 and, simultaneously, the electric conductivity of 94.6% International Annealed Copper Standard (IACS). The microstructure, featuring graphene particles more or less homogeneously distributed along the grain boundaries, consists of fine grains and numerous strengthening twins, the formation of which is supported as the graphene particles aggravate the movement of dislocations along the preferential slip systems. The occurring structural phenomena (grain boundaries, twinning, texture, etc.) directly influence the mechanical (microhardness), physical (dilatation), and electric properties of the composite.