Insights into the stable preferred growth direction of rods in the colony of Al2O3/ZrO2 (Y2O3) eutectics

The Al2O3/ZrO2 (Y2O3) eutectics were prepared by the melt-grown and seeding melt-grown methods, two non-directional solidification methods. We identify the three-dimensional morphology and crystallographic orientations of the Al2O3/ZrO2 (Y2O3) eutectics using the focused ion beam milling with electron backscattered diffraction and the transmission electron microscopy. The results show that in the colony, there are three parts of the ZrO2 (Y2O3) phase composed of interconnected three-level rods. The crystallographic orientation of the colony axis is variable, but the growth directions of the rods show a commonality, <2̅ 0 2 1 >A, in the Al2O3/ ZrO2 (Y2O3) eutectics, which has been also clarified by the interface structure analysis. The analysis of the preferred growth orientation not only enlightens the growth mechanism of Al2O3/ZrO2 (Y2O3) eutectics but also provides a method for the design of novel eutectics.