Influence of fibers on the microstructure and compressive response of directional ice-templated alumina ceramics

Directional ice-templated ceramics have unique lamellar porous channels between ceramic walls which run from bottom to top of the samples. This highly oriented morphology results in the anisotropy in mechanical properties both parallel and perpendicular to freezing direction. In this research, fiber-enhanced ice-templated porous ceramics were fabricated by introducing fibers into alumina slurry for freezing. The trans-lamellar fiber bridges connecting adjacent ceramic walls were formed by adjusting the aspect ratio of fibers and freezing velocity, which greatly enhanced the compressive response in two directions and weakened the anisotropy in mechanical properties of the directional ice-templated ceramics. The results showed that the of fiber bridges increased with the increase of fiber aspect ratio and the longitudinal and transverse mechanical properties increased by 73.5% and 232.6%, respectively.