The Effect of Alumina Addition on Phase Transformation and Mechanical Properties in Partially Stabilized Zirconia

摘要

The isothermal tetragonal-to-monoclinic phase transformation and mechanical properties of K_(IC) and fracture strength are investigated in ZrO_2-5mass%Y_2O_3 containing 0-12mass% Al_2O_3. With increase in alumina content, the phase transformation is suppressed; the nucleation rate tends to be suppressed but the growth rate is not changed. K_(IC), increases from about 5 to 6-6.5 MPa√m and the bending strength increases from about 300 to 700 MPa by the addition of alumina. These phenomena are attributed to the formation of an amorphous grain boundary phase. Formation of this phase increases the cohesion between grains.