Effect of multi-groove reinforcement strategy on Cu/SiC surface composite fabricated by friction stir processing

Abstract

In the present study, Cu/SiC surface composite was fabricated by friction stir processing (FSP) via multi-groove technique eyeing to improve SiC dispersion in copper matrix and hence improving mechanical and tribological behaviour. Microstructural features revealed more uniform dispersion of SiC particles in copper matrix when fabricated through multi-groove technique (MGT) as compared to single groove technique (SGT). The interface between copper matrix and SiC particles were clean without any obstruction/interruption in the form of voids or pores or intermediate phases formed which indicated excellent interfacial bonding. Furthermore, the obtained microstructure revealed drastic grain refinement in FSPed copper without reinforcement and the composites fabricated through SGT and MGT and the reduction in grain size was more for the composites fabricated by MGT. Tensile tests revealed incremental behaviour over strength with increase in number of grooves although it was far less as compared to base copper. Fractured surfaces of composites fabricated by both techniques (SGT and MGT) indicated reduction in ductility. However, results obtained for FSPed copper without reinforcement showed higher strength and ductility as compared to base copper. It was also demonstrated that incorporation of SiC particles in copper matrix improved hardness and wear resistance and it further enhanced with increased number of grooves. The wear mechanism changed with introduction of SiC particles in copper matrix and was supposed to be because of reduction in friction coefficient.