Characterization of copper–graphene nanocomposite block prepared by friction stir additive manufacturing

Abstract This study explores the friction stir additive manufacturing (FSAM) of copper enhanced with graphene nanosheets, aiming to improve the mechanical and electrical properties of the material. Copper sheets and graphene nanosheets were used as raw materials and a systematic FSAM process was employed to create a multi-layered composite. Microstructural analysis revealed defect-free layers with well-distributed graphene, particularly in stir and restirring zones. The incorporation of graphene significantly enhanced the ultimate tensile strength (UTS) of the composite to 321 MPa, a 56% increase over pure copper. Electrical conductivity also improved, reaching 108% IACS compared to 104% for pure copper. This enhancement is attributed to the graphene’s superior electron transport pathways and its effective bonding within the copper matrix. The presence of graphene in the Imp.Cu-nano sample reduced the exposure area to the corrosive solution, improved the microstructure, and enhanced corrosion resistance. Fracture surface analysis showed smaller dimples in the composite, indicating increased strength but reduced ductility compared to pure copper. Hardness measurements confirmed higher hardness values in the upper layers of the composite due to finer grain structures. These findings suggest that graphene-reinforced copper composites produced by FSAM hold significant promise for applications requiring enhanced mechanical strength and electrical conductivity.