Chain structure in the unidirectionally solidified Al_2O_3-YAG-ZrO_2 eutectic composite

摘要

Three-dimensional images of the unidirectionally solidified Al_2O_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_2O_3 and YAG phases in an Al_2O_3-YAG-ZrO_2 ternary eutectic specimen was lower than that of the Al_2O_3 and YAG phases in an Al_2O_3-YAG binary eutectic specimen and that the domain size of branching of the YAG and Al_2O_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_2O_3 phase and at the phase boundaries between Al_2O_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_2O_3 phases. Chain structures between Al_2O_3/YAG and Al_2O_3/ZrO_2 were formed due to the frequent branching of the three constituent phases.