CRACK GROWTR RESISTANCE BEHAVIOR AND THERMAL SHOCK RESISTANCE FOR ZrO_2+ Al_2O_3 LAMINATED CERAMICS

The crack growth resistance behavior of Al_(2)O_(3)+ZrO_(2)monolayer and laminated ceramics were determined by indentation-strength method. The properties of thermal shock resistance of these two materials were also estimated by indentation method. The relationship between the R-curve, the thermal shock resistance properties and the mechanism of strengthening and toughening were studied. The results indicate that the Al_(2)O_(3)+ZrO_(2)laminated ceramics is not sensitive to the surface cracks. Indentation thermal shock test shows that the critical temperature difference of the Al_(2)O_(3)+ZrO_(2 )laminated ceramics is 400 ℃, which is 150 ℃ higher than those of monolayer ceramics. The fracture resistant mechanism and thermal shock resistance of the two materials are closely related to strengthening and toughing mechanisms.The R-curve and thermal shock resistance properties are improved and the transformation effect are strengthened by the surface compressive stress effect.