Strength enhancement of coarse-grained cemented carbide by incorporating ZrO2 particles into ceramic grains

A new approach was proposed for preparing high-strength coarse-grained WC-Co cemented carbides by introducing ZrO 2 particles into the WC grains. The particles within the cemented carbide were quantitatively characterized, and it was found that the particle parameters changed with the contents of the nanoscale ZrC and WC-Co composite powder added in the raw materials. At an appropriate combination of ZrC and WC-Co composite powder, the coarse-grained cemented carbide achieved the highest fracture strength. The mechanisms responsible for the strength enhancement were disclosed, which were associated with the impact of the in-grain ZrO 2 particles inhibiting WC dislocation movement while enabling stress transfer by deformation accommodation, thereby delaying the pre-mature fracture failure of the cemented carbide. The findings in this study provide new insights in the development of high-strength metal-ceramic composites. • A new approach was proposed for introducing ZrO 2 particles into ceramic grains. • The prepared composite exhibited simultaneously high hardness and high fracture strength. • Strengthening mechanisms were disclosed by detailed characterizations on the effects of in-grain ZrO 2 particles.