In-situ TEM observations of tetragonal to monoclinic phase transformation in ZrO₂T-2 mol% Y₂O₃ ceramics

In-situ TEM observations of tetragonal to monoclinic phase transformation in ZrO₂-2 mol% Y₂O₃ ceramics were performed under the action of electron beam heating. The results show that the nucleation and growth of m-ZrO₂ martensite and its final morphology are dependent upon the microscopic content and distribution of Y₂O₃. In microareas with lower Y₂O₃ content and homogeneous distribution, the m-ZrO₂ martensite nucleates and grows by twins, finally forming parallel laths. But in microareas with higher Y₂O₃ content and heterogeneous distribution, single plate of m-ZrO₂ martensite is first formed, and simulates the appearance of other martensite plates, finally forming N or Z shaped skeleton.