Insights into the crystallographic orientation rotation of rods and lamellae within colonies of Al2O3-ZrO2(Y2O3) eutectic ceramics

Al 2 O 3 -ZrO 2 (Y 2 O 3 ) eutectic ceramics are promising high-temperature structural materials with excellent thermal stability and mechanical properties. Crystallographic orientation control is effective for tuning their performance. Herein, we investigated the crystallographic orientation rotation of Al 2 O 3 and ZrO 2 phases in the rod-like and lamellar micro-regions into the core of the colonies of Al 2 O 3 -ZrO 2 (Y 2 O 3 ) eutectic ceramics prepared by the seeding melt-grown method. Results show that ZrO 2 phases exhibit diverse growth directions with gradual rotation in both regions. However, Al 2 O 3 phases exhibit distinct rotational behaviors depending on the morphology: in lamellar regions, the crystallographic orientations of both Al 2 O 3 and ZrO 2 phases rotate synchronously, with the misorientation angle per unit length relative to an initial position reaching up to 2.09°·μm −1 ; in rod-like regions, the Al 2 O 3 phase shows negligible rotational displacement. Crystallographic orientational rotation behaviors were measured in these melt-grown eutectic ceramics, providing a research basis for the solidification of oxide eutectics.