Chain structure in the unidirectionally solidified Al(2)O(3)-YAG-ZrO(2) eutectic composite

Three-dimensional images of the unidirectionally solidified Al(2)O(3)-YAG-ZrO(2) eutectic composite were obtained by micro-X-ray tomography. Reconstructed three-dimensional images revealed that the frequency of branching of Al(2)O(3) and YAG phases in an Al(2)O(3)-YAG-ZrO(2) ternary eutectic specimen was lower than that of the Al(2)O(3) and YAG phases in an Al(2)O(3)-YAG binary eutectic specimen and that the domain size of branching of the YAG and Al(2)O(3) phases was approximately twice as high as the lamellar spacing between the two phases. The ZrO(2) phase was mainly located in the Al(2)O(3) phase and at the phase boundaries between Al(2)O(3) and YAG, but not in the YAG phase. The branching of the ZrO(2) phase occurred more frequently in comparison with the YAG and Al(2)O(3) phases. Chain structures between Al(2)O(3)/YAG and Al(2)O(3)/ZrO(2) were formed due to the frequent branching of the three constituent phases.