Copper matrix composites reinforced by aligned carbon nanotubes: Mechanical and tribological properties

The hardness, strength, and abrasion resistance of copper for electrical contact materials is poor. Thus, we aligned carbon nanotubes in Cu matrix composites through die-stretching for their excellent mechanical properties and abrasion resistance. The Cu matrix composites with varying CNTs volume fraction from 0 to 10 vol.% were fabricated under protective atmosphere sintering of a mixture of Cu powders and Ni/Cu coated CNTs. This was followed by forging and die-stretching. The CNTs were uniformly dispersed in the dense composites, and the trend of their alignment along the stretching direction was obvious. The composites were anisotropic, and their mechanical properties and abrasion resistance increased obviously with the addition of CNTs. The 5 vol.% CNTs/Cu composite showed the best hardness, tensile strength, and abrasion resistance. The mechanisms underlying the improved mechanical and tribological behavior were evaluated, and this research provides novel ideas and technology for the distribution and directional alignment of CNTs in the matrix. (C) 2016 Elsevier Ltd. All rights reserved.