Temperature dependence of flexural strength and microstructure of Al2O3/Y3Al5O12/ZrO2 ternary melt growth composites.

New Al₂O₃/Y₃Al₅O₁₂(YAG)/ZrO₂ ternary Melt Growth Composites (MGCs) with a novel microstructure have been fabricated by unidirectional solidification. These MGCs displayed superior high-temperature strength characteristics. The flexural strength increases progressively in the range 650–800 MPa with a rise in temperature from room temperature up to 1873 K. These excellent high-temperature characteristics are closely linked to such factors as: a microstructure consisting of three-dimensionally continuous and complexly entangled single-crystal Al₂O₃ with a hexagonal structure, single-crystal YAG with a garnet structure and fine ZrO₂ with a cubic structure; characteristic dimensions of the microstructure of Al₂O₃/YAG/ZrO₂ ternary eutectic ceramics of around 2–3 μm for YAG, around 2–3 μm for Al₂O₃ and around 0.4–0.8 μm for ZrO₂; and the fact that no amorphous phase is formed at interfaces between any of the phases. [ABSTRACT FROM AUTHOR]