Achieving high strengthening efficiency of graphene oxide in Cu matrix composites by introducing ex-situ interfacial TiC

Abstract

Through effective interface regulation, the interfacial bonding strength between graphene oxide (GO) and Cu matrix can be significantly enhanced, thereby greatly improving the strengthening efficiency of GO and achieving synergistic enhancement of strength and ductility of Cu matrix composites (CMCs). In this study, on the premise of ensuring the structural integrity of GO, nanoscale TiC is synthesized by the reaction of fragmented GO and Ti powders on the surface of intact GO through pressure-less spark plasma sintering (SPS). The results demonstrate that the TiC modified GO (TiC@GO) can significantly enhance the mechanical properties of CMCs. Specifically, the TiC@GO/Cu composite exhibits an ultimate tensile strength that is 18.5 % and 8.9 % higher than that of pure copper and GO/Cu composite, respectively, while maintaining an exceptional elongation of 32.9 %. The ex-situ nano-scale TiC interfacial phase on the GO surface not only forms a strong interface bonding with GO, but also forms a large number of semi-coherent interfaces with the Cu matrix. By significantly enhancing the interfacial shear strength, TiC@GO achieves an ultra-high strengthening efficiency in the CMCs, reaching 297.7. The strength and ductility of TiC@GO/Cu composite are synergistically improved through the optimization of load-transfer efficiency and effective interfacial dislocation accumulation. In addition, the results of first-principle calculations combined with experimental characterization reveal a lower interfacial energy and higher interfacial shear strength between TiC and Cu, which facilitates tortuous crack propagation paths before fracture.