Effects of nano-alumina on mechanical properties and wear resistance of WC-8Co cemented carbide by spark plasma sintering

The effects of adding different nano-alumina on the structure, mechanical properties and wear resistance of WC8Co cemented carbide during spark plasma sintering (SPS sintering) were investigated. The results show that the nano-alumina is dissolved in the Co phase, which results in a larger proportion of FCC-Co in the gamma phase on the surface of the WC-Co cemented carbide. Under the scanning electron microscope, it is observed that the grains of cemented carbide are refined, and when the addition amount is 0.5 wt%, the effect of WC grain refinement is the most significan. The hardness, flexural strength and fracture toughness showed a trend of increasing first and then decreasing with nano-alumina added. The peak value is reached when the nano-alumina content is 0.5 wt%, Which means that the alloy has the best combination of mechanical properties, that is, hardness reaches 1716 HV30, bending strength reaches 2728 MPa, and fracture toughness is 12.95 MPa center dot m(1/2). Adding nano-alumina is beneficial to improve the wear resistance of cemented carbide. As a matter of course, when the content of nano-alumina is 0.5 wt%, the friction coefficient is the lowest, the wear rate is the smallest, and the wear resistance is the best.