Abstract
A repeated co-extrusion process was used to fabricate fibrous composites of Al2O3 and ZrO2. A bundle of feedrods composed of ordinary arranged Al2O3 and ZrO2 green rods was co-extruded through a 7:1 reduction die. After the first co-extrusion, the individual pieces were bundled and co-extruded again, reducing the lateral size of each phase and multiplying the number of continuous monofilaments. The extrudates were pressureless sintered at 1600oC for 3h after the decomposition of organic residuals. First and second extrusion steps produced composites with cracks due to the mismatch in thermal expansion coefficient between Al2O3 and ZrO2 ceramics. Finally, a crack-free, high density Al2O3/ZrO2 composite could be obtained after 3rd extrusion step, though the filaments were not found to be continuous. Mechanical properties of the composites were evaluated and discussed on the basis of the microstructure.
