THE EFFECT OF SUBZERO TREATMENT ON THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF Y_2O_3-ZrO_2 CERAMIC

The effect of subzero treatment on the microstructure and mechanical properites of Y_2O_3- ZrO_2 ceramic have been investigated by TEM,X-ray diffraction and test of mechanical properties.It was shown that the microstructre of 3Y-PSZ after subzero treatment by liquid nitrogen exhibits very long and parallel laths of m-phase and some microcracks around the larger and finer lath of m-phase may be discovered.Suitable subzero treatment can improve the strength and toughness of Y-PSZ efficiently because of decreasing the stability of t-phase and incresing the amount of t-m transformation when exerting a stress.However,when the time of subzero treatment exceeds,the over aging effect may arise.which can decrease the strength and toughness of the material.