Fabrication and performance of SiC-reinforced Cu: Role of the aspect ratio of the SiC reinforcement phase

In this study, SiC particle (SICP)- and SiC whisker (SICW)-reinforced Cu composites were prepared by pulse intermittent deposition and subsequent spark plasma sintering (SPS). After electrodeposition, the formation of Cu-coated SICP and SICW core–shell structures solved the problem of agglomeration of the second phase during the subsequent sintering. In addition, the wetting layer of Cu increased the bonding strength of the interface between Cu and the second phase. The strength of SICP-reinforced Cu was higher than that of pure Cu at the expense of elongation and thermal conductivity. Compared to SICP-reinforced Cu, SICW-reinforced Cu exhibits significantly higher strength, plasticity and thermal conductivity. The externally applied load was transferred from a soft Cu matrix to stiff SICWs, thus increasing the yield strength of the composites. Furthermore, bridge cracks, crack deflection, and whisker pull-out mechanisms improved the elongation of the composite. This work reveals the relevance of the strengthening mechanism and the aspect ratio of the reinforced phase systematically and provides an advanced pathway to fabricate high-performance metal–matrix composites by designing discontinuous second phases with tailored aspect ratios.