Nanoindentation and wear behaviour of copper based hybrid composites reinforced with SiC and MWCNTs synthesized by spark plasma sintering

In this study, copper based hybrid composites comprising of multiple reinforcements like silicon carbide and multiwalled carbon nanotubes were synthesized via mechanical milling followed by spark plasma sintering. The weight fraction of silicon carbide was fixed to 4 wt.% and that of multiwalled carbon nanotubes was varied from 1 to 4 wt.% in the steps of 1 wt.%. Microstructural observations carried using scanning and transmission electron microscopy showed uniform dispersion of both silicon carbide and multiwalled carbon nanotubes. Hardness behaviour was analysed using microindentation and nanoindentation at various local regions of the hybrid composites. The experimental results showed that the multiple reinforcements were effective in improving the hardness and elastic modulus. In addition to this tribological properties were evaluated using pin on disc tribometer under variable normal loads. The wear rates of all hybrid composites were low compared to that of pure copper revealing significant strengthening by both the reinforcements. However the electrical conductivity of hybrid composites were found to decrease with the increase in carbon nanotubes content.