Properties of WC-Co Cemented Carbide Reinforced with Yttria-Stabilized Zirconia Nanoparticles

To produce strong and wear-resistant tools for the rock drilling industry, the most commonly used metal matrix composites contain the reinforcing phase of cemented carbide. There are numerous research reports on attempts to improve the performance of WC-Co composites. The paper is a continuation of previously reported research on the SPS-processed WC–6 wt.%Co metal matrix composites with yttria-stabilized zirconia (YSZ) addition in amounts of 4 wt.% and 10 wt.%. The sintered specimens were polished and underwent the microindentation tests with a Vickers shape diamond tip. The following parameters were measured: stiffness S, the Poisson number ν, indentation creep CIT, relaxation RIT, indentation hardness HIT, indentation Vickers hardness HVIT, Martens hardness HM, reduced modulus E*, and indentation elastic modulus EIT. The tests revealed hardness values of 16.2–17.0 GPa and indentation elastic moduli in the range of 607–670 GPa. Moreover, respective plastic and elastic parts of the indentation work Wplast and Welast were determined. It was found that YSZ addition slightly reduced hardness and modulus, but all the three wear parameters, H/E, H3/E2, and 1/(E2H), increased after addition of zirconia. Specifically, for 10 wt.% ZrO2 H/E increased by 5%, H3/E2 by 7%, while 1/(E2H) by 27% compared to 94WC–6Co composition.