Competitive growth of Al 2 O 3 / YAG /ZrO 2 eutectic ceramics during directional solidification: Effect of interfacial energy

The microstructure evolution and growth behavior of the Al 2 O 3 /Y 3 Al 5 O 12 ( YAG )/ZrO 2 ternary eutectic ceramics during directional solidification were well investigated. During directional solidification of the Al 2 O 3 / YAG /ZrO 2 ternary eutectic ceramics, { } Al 2 O 3 paralleled with {001}ZrO 2 while they did not parallel with {001} YAG at the same time in the competitive growth stage. All of the interfaces parallel to each other finally. The area percentage of the Al 2 O 3 /ZrO 2 and YAG /ZrO 2 interfaces are 40.4 ± 0.2% and 30.8 ± 0.1%, respectively, higher than that of the Al 2 O 3 / YAG (28.8 ± 0.2%). The content of Al 2 O 3 and YAG phases are 39.9% and 41.1%, respectively, almost double of that of ZrO 2 . The interfaces of Al 2 O 3 /ZrO 2 and YAG /ZrO 2 are shorter and more dispersed than that of the Al 2 O 3 / YAG . It was found that the interfacial energy of Al 2 O 3 /ZrO 2 and YAG /ZrO 2 interfaces are lower than that of Al 2 O 3 / YAG . It can be concluded that interfacial energy plays a decisive role in affecting the crystallographic orientation and interfaces distribution in the Al 2 O 3 / YAG /ZrO 2 eutectic since the interfaces of Al 2 O 3 /ZrO 2 and YAG /ZrO 2 with lower interfacial energy can be formed more easily during directional solidification. Therefore, the contents of Al 2 O 3 /ZrO 2 and YAG /ZrO 2 interfaces are higher. This study can provide theoretical guidance for interface design of multi‐phase materials.