Wear resistance and fracture mechanics of WC-Co composites

Manufacturing of WC-Co composites using the electroless precipitation method at different sintering temperatures of 1100, 1250, 1 350 and 1 500 degrees C was successfully achieved. The chemical composition of the investigated materials was 90 wt.% WC with 10 wt.% Co, and 80 wt.% WC with 20 wt.% Co. The specific density, densification, and Vickers microhardness measurements were found to increase with increased sintering temperature for both the WC-Co compositions. The composites of tungsten carbide with 10 wt.% Co had a higher specific density and Vickers microhardness measurements than those for the composites of tungsten carbide with 20 wt.% Co. Composites with WC-10 wt.% Co had better wear resistance. The stress-strain and transverse rupture strength increased monotonically with the increase in sintering temperatures, agreeing with the material hardness and wear resistance behavior. Fractographical scanning electron microscopy analysis of the fracture surface demonstrated a rough characteristic conical shape failure in the direction of the maximum shear stress. A proposed mechanism for the formation of the conical fracture surface under compression testing is presented.