Synergistic influence of carbon nanotube-graphene oxide hybrid and nanosized interfacial TiC on the mechanical performance of Cu matrix composites

Reinforcement architecture and interfacial structure are two key factors affecting the performance of composites. Herein we attempted to achieve a comprehensive improvement of mechanical properties of carbon nanomaterials (CNMs) reinforced Cu matrix composites by means of reinforcement structure construction and interface structure optimization. Graphene oxide (GO) and acid-treated carbon nanotubes (AT-CNTs) were self-assembled into a GO-CNT hybrid structure through an ultrasonic mixing method, and then used as reinforcement of Cu matrix composite through the powder metallurgy method. The strengthening efficiency of GO-CNT hybrid was significantly higher than that of individual CNTs or GO, which could be attributed to the stable interconnected architecture of GO-CNT hybrid formed through sp3 hybridized C–C bonds and the larger interfacial area between them and Cu matrix. In addition, aiming at the issue of poor interfacial adhesion between the GO-CNT hybrid and Cu matrix, TiC nanoparticles were introduced onto the surface of GO-CNT hybrid through a pressureless spark plasma sintering strategy. The TiC nanoparticles can improve the interfacial wettability and optimize the interfacial bonding state. TEM results confirmed a semi-coherent interfacial lattice matching relationship between TiC nanoparticles and Cu matrix, which was conducive to forming robust interfacial bonding. Through the construction of hybrid reinforcement and the introduction of nanosized interfacial TiC, the GO-CNT hybrid reinforced Cu matrix composite has obtained ultra-high strengthening efficiency, and exhibited satisfied combination of strength and ductility. This study can provide a referential strategy for the comprehensive performance optimization of CNMs reinforced metal matrix composites.