Affecting the Properties of Copper–Graphene Electroconductive Composite by Severe Plastic Deformation

Modern electroconductive materials involve copper‐based carbon‐enhanced composites featuring convenient mechanical properties and, simultaneously, favorable electric conductivity. Such composites can be processed by deformation/thermomechanical treatments to introduce advantageous microstructures, further enhancing their performance. The study features powder‐based copper–carbon (Cu/C) composites, fabricated from chemical vapor deposition‐prepared powder mixture by a direct consolidation using the rotary swaging method, which enables to eliminate the typical (costly and time consuming) preparation steps of consolidation and sintering. The directly consolidated Cu/C composites were further processed by the severe plastic deformation method of high‐pressure torsion (HPT), introducing severe shear strain and high pressure and thus providing fine‐grained microstructures. The consolidated composites were processed with two HPT revolutions. The results showed that the final microstructures and properties were primarily influenced by the carbon content within the prepared powder mixture; although the HPT‐processed composites featured homogeneous fine‐grained microstructures with the average grain sizes of 2–3 µm, the sizes of the graphene particles varied. The Vickers microhardness exceeded 100 HV0.1 for all the samples, and the electric conductivity varied between 98.8% and 102.1% IACS (International Annealed Copper Standard).