The effect of prestressing on the fracture toughness of ZrO2-(3, 4) mol % Y2O3 ceramics

It is shown that the fracture toughness of prestressed ZrO2-(3, 4) mol % Y2O3 ceramics monotonically increases, the growth being as high as ∼50% of the initial value. It is believed that prestressing causes slow isothermal martensite transformation of some grains in the material. During mechanical tests, the degree of transformation rises, which shows up as increased fracture roughness.