Regulating the mechanical properties and electrical conductivity of CNTs/Cu composites by tailoring nano-sized TiC on the surface of intact CNTs

Abstract Strengthening effect of carbon nanotubes (CNTs) reinforced metal matrix composites (MMCs) mainly depends on the interfacial bonding strength which has a decisive influence on comprehensive properties of the composites. However, in CNTs reinforced Cu matrix composites, poor interface bonding due to the lack of wettability between CNTs and Cu matrix has become a bottleneck problem restricting the load-transfer capacity of CNTs. Different from the conventional thoughts of producing interfacial carbides by in-situ reaction with CNTs which will lead to deterioration of structural integrity of CNTs, a novel strategy is used by forming TiC on the surface of intact CNTs through solid phase reaction between the pre-milled CNTs and the Ti powders. The mechanical properties of the composites can be regulated by tailoring the morphology and amount of TiC decorated at the interface. Strong interfacial bonding achieved due to the specially designed interface structure which contributes to the dramatic improvement of strengthening efficiency of CNTs and benefits the plastic deformation of Cu matrix. Consequently, a simultaneous enhancement of tensile strength (281 MPa) and tensile elongation (20.1%) is achieved in the composite with TiC decorated at the interface, and a super high strengthening efficiency (135) is realized. The tactic used in our study can provide a reference for the preparation of other CNTs/MMCs.