Mechanical properties of Al2O3-ZrO2 composite ceramics

Density (rho) dependences of the bending strength (sigma) and the Vickers hardness (H-v) of the Al2O3-ZrO2 [Y2O3 partially stabilized ZrO2 (Y-PSZ)] composite ceramics were expressed by power laws of sigma proportional to rho and H-v proportional to rho(m), respectively. The value n decreased largely when the composite contained 20-50 wt% Al2O3. The change of value ?n was small in this range. The values of n and m depend upon the fractal dimension (d) over bar, which is related to the structure of composite ceramics. The change of both values in the Al2O3 content of 20-50 wt% shows that the structure changes from ZrO2 type to Al2O3 one. The tetragonal phase of ZrO2 component was highly stabilized in the composite ceramics. The relationship between the value of bending strength and quantity of tetragonal phase was not clear.