A study of size effects in bioinspired, “nacre-like”, metal-compliant-phase (nickel-alumina) coextruded ceramics

The ceramic process method of coextrusion has been used to manufacture bioinspired alumina ceramics in the form of “nacre-like” brick-and-mortar microstructures, where strength is provided by 90 vol.% of alumina bricks whereas ductility is provided by limited inter-brick displacements in a metallic nickel mortar. By refining the already coarse structure resulting from coextrusion, alumina ceramics have been created with high R-curve fracture toughness values exceeding 15 MPam1/2, although strength levels did not exceed 200 MPa due to cracking in the nickel/alumina interfaces, rather than within the metallic mortar.284