An electroless plating and planetary ball milling process for mechanical properties enhancement of bulk CNTs/Cu composites

CNTs/Cu composite powders were prepared by an electroless plating and planetary ball milling process. The structure of composite powders was investigated. Results showed that Cu particles are homogeneously deposited on CNTs surface, and CNTs are deeply embedded into Cu matrix after milling, which play an important role in the dispersion and the wettability of CNTs within matrix and subsequently in the mechanical properties of composites. And the bulk CNTs/Cu was fabricated by vacuum sintering, re-pressing and re-sintering, and cold drawing process. It revealed that comparing pure Cu and composite without electroless plating, the tensile strength of composite with electroless plating increases obviously, up to 207 MPa. SEM images revealed that agglomeration is the main reason of deteriorating mechanical properties of composites. Finally, higher strength composites were successfully obtained by cold drawing. Results demonstrated that it can significantly improve the mechanical properties of the composites. Also, the tensile strength and the yield strength are up to 311 MPa and 185 MPa, respectively. SEM images clearly revealed that it is the dispersion and directional distribution of CNTs in matrix that further improve the strength of composites in drawing orientation. The load transfer theory was also employed to testify the results, effectively.