Microstructure and mechanical properties of multi-cation containing α-sialons

Dense Y-, Yb- and (Y + Yb)-doped α-sialons containing 2 wt.% extra liquid phase were fabricated by hot pressing. The results show that the elongated grains morphology can be obtained by partially substituting Yb with Y as a modifying cation, and hence improve the toughness of the materials. An additional intermediate holding step during sintering has no obvious effect on the microstructures and the mechanical properties. Post-heat treatment can further facilitate the growth of elongated α-sialon grains and increase the toughness of the materials. All the materials exhibited very similar high hardness of over 20 GPa.