This study examined the effect of the 3Y-TZP (3 mol% yttria stabilized tetragonal zirconia polycrystal) content on the mechanical properties and machinability of Al2O3 ceramics. The fracture toughness and biaxial strength increased with increasing 3Y-TZP content. The increasing amount of tetragonal ZrO2 and finer grain size of Al2O3 appear to be responsible for the high fracture toughness and biaxial strength, respectively. The thermal-induced residual stresses that probably account for the enhancement of fracture toughness were also calculated. The cutting force for a fully densified Al2O3 ceramic decreased with decreasing depth of cut or increasing cutting speed. Severe tool wear was observed during the cutting process due to the high hardness of the fully densified Al2O3 ceramic.

Keywords: Ceramics. Composites; Sintering; Machining; Microstructure; Strength