Synergistic optimization of properties in carbon nanotubes reinforced Cu matrix composites prepared by co-deposition

Electrochemical co-deposition is a highly effective approach for achieving composites with specific composition and homogeneous distribution of reinforcement by manipulating electrolysis parameters. In this study, laminated carbon nanotubes reinforced copper composites (CNTs/Cu) were prepared through co-deposition and subsequent spark plasma sintering (SPS). In contrast to conventional powder metallurgy, the co-deposition method enables simultaneous deposition of CNTs and Cu particles while preserving the structural integrity of CNTs. It was observed that the CNTs were embedded within the growing Cu grains, resulting in a tightly bonded interface between them. The content of CNTs in composite deposited under current density of 0.5, 0.1 and 1.5 A dm−2 is measured to be 0.51 vol%, 1.05 vol% and 1.31 vol%, respectively. The average grain size exhibited a significant reduction, decreasing from approximately 33.4 μm for pure Cu to 3.3 μm for the CNTs/Cu composite deposited under current density of 1.5 A dm−2. Compared to pure Cu, the composite exhibited a significantly enhanced yield strength of 254 MPa, which is approximately 5 times that of pure Cu, the ultimate tensile strength improved to 290 MPa with an elongation of 15%, and the strengthening efficiency was calculated to be as high as 476. Load transfer is the primary contribution to the strength of the composites, followed by an increase in dislocation density and grain refinement. Meanwhile, the electrical conductivity of the composite with optimized condition demonstrated a high value of 94.4%IACS. The co-deposition method can facilitate the homogeneous dispersion of CNTs, enhance interfacial bonding, improve the structural integrity of CNTs, thereby enabling synergistic optimization of the properties of laminated CNTs/Cu composites.