Synergistic strengthening effect of tungsten carbide (WC) particles and silicon carbide whiskers (SiCw) on mechanical properties of Cu–Al2O3 composite

Cu–Al2O3 composites are widely used in electrical contact fields because of their excellent electrical conductivity, thermal conductivity and arc erosion resistance. (WC + SiCw)/Cu–Al2O3 composites with better properties were prepared by powder metallurgy combined with an internal oxidation process that introduced micron-sized WC particles and SiCw into the Cu–Al2O3 composite. The synergistic strengthening mechanism effect of nano-Al2O3 particles, micron-sized WC particles and SiCw in copper matrix composites was analyzed. The results show that there is a semi-coherent interface between the nano-Al2O3 particles and the copper matrix. The ultimate tensile strength of the (1WC + 2SiCw)/Cu–Al2O3 composite is 531.6 MPa, which is 12.7% and 4.5% higher than that of the Cu–Al2O3 composite and the SiCw/Cu–Al2O3 composite, respectively. According to theoretical calculations and an analysis of the strengthening mechanism, the contributions of the Orowan strengthening and load transfer strengthening mechanism in the (1WC + 2SiCw)/Cu–Al2O3 composite are 27.3% and 16.6% respectively. The synergistic strengthening effect of particles and whiskers contributed 6.0% to the tensile strength of the (1WC + 2SiCw)/Cu–Al2O3 composite.