Fabrication of CNT/Cu composites with enhanced strength and ductility by SP combined with optimized SPS method

Mono-dispersed and homogeneous carbon nanotube (CNT)/copper (Cu) composite powders were fabricated by spraying pyrolysis (SP) method successfully. Subsequently, CNT/Cu composites were obtained by spark plasma sintering (SPS) at sintering temperature ranged from 1023 to 1223 K (70-90% melting point of pure Cu). The mechanical properties, micro-morphology and interface microstructure of CNT/Cu composites were measured and characterized. The results reveal that Cu nano-particles (NPs) coated on the CNT surface are conducive to improving the wettability of CNT within matrix and reducing the interface energy between matrix and CNT, and finally stable interface structure is established. The traditional trade-off tendency between strength and ductility is balanced in the CNT/Cu composites, which are sintered at 1223 K. The ultimate tensile strength (UTS) shows 344 MPa and the elongation is 19.6%, which owing to the improvement of CNT-Cu interface bonding. At last, the role of interfacial bonding extent played in determining the load transfer efficiency of CNT is discussed.