Mechanical response and failure behavior of fiber enforced porous ceramics by directional freeze-casting

Abstract The anisotropy of compression response and energy absorption of fiber enforced porous ceramics by directional freeze-casting have been investigated to infer the failure mechanism. An enhanced porous ceramic structured with fiber-bridging-lamellar walls was synthesized by directionally freezing nano spherical alumina suspension with different fiction of alumina microfibers. Due to the anisotropic microstructure, the mechanical properties of the freeze-casting ceramics are closely related to the orientation of the applied stress. Different orientations of loads correspond to the different deformation mechanisms under the load. The compression experiments under different orientations were carried out, and the failure mechanism was judged by the energy absorption characteristics and compression response. In contrast to traditional freeze-casting ceramics, the scaffolds supported with fiber bridges have higher mechanical properties (up to 15 MPa in compressive strength and density up to 0.76 g/cm3), and their failure behavior tends to plastic fracture, which increases toughness and availability without decreasing porosity and pore size.