Transformation and Microcrack Toughening as Complementary Processes in ZrO2-Toughened Al2O3

摘要: Both tetragonal (t) and monoclinic (m) ZrO2 particles in ZrO2-toughened Al2O3 can give rise to toughening. In the stress field of propagating cracks, t-ZrO2 undergo stress-induced t→m transformation, residual stresses around already-transformed m-ZrO2 cause microcracking. The transformed crack tip fields do not, however, also appreciable toughening increments via these distinct mechanisms are comparable. It appears that optimally fabricated Zr02-toughened Al2O3's should contain a mixture t- m-ZrO2.