Fabrication of novel multilayer Al2O3-(m-ZrO2)/t-ZrO2 fibrous ceramics composites

A novel layered microstructure in the Al₂O₃/ZrO₂ composites system was fabricated by the multipass extrusion method. The microstructure consisted with very fine alternate lamina of Al₂O₃-(m-ZrO₂) and t-ZrO₂. The composites were designed in such a way that a small group of 7 cylindrical alternate layers of Al₂O₃-(m-ZrO₂) and t-ZrO₂ made a concentric microgroup around 40 μm in diameter, with a common boundary layer between the adjacent groups. The thickness of both layers was around 2-3 μm. The microstructure was unidirectionally aligned throughout the composites. The composite microstructure was fibrous due to the unidirectional orientation of these microgroups. Detailed microstructure of the fabricated composites was characterized by SEM. The effect of the concentric layered microstructure on mechanical behavior was discussed. Material properties such as density, bending strength, Vickers hardness and fracture toughness were measured and evaluated depending on different sintering temperatures.