Mechanical behaviour of additively manufactured ceramic–epoxy interpenetrating phase composites with bioinspired nacre-like architecture

Integrating bioinspired design principles with additive manufacturing offers a promising approach to enhancing the mechanical performance of brittle ceramics. In this study, nacre-like ceramic–epoxy composites were fabricated through a hybrid process combining photopolymer-based additive manufacturing (AM), sintering, and epoxy infiltration. Nacre columnar and nacre sheet architectures were printed via digital light processing using a silica-filled photopolymer resin, followed by debinding and sintering at 1300 °C and 1500 °C to obtain nacre-like ceramic scaffolds, which were subsequently infiltrated with epoxy. Microstructural analyses confirmed effective epoxy infiltration, which sealed sintering-induced cracks and pores, thereby enhancing interfacial bonding and delaying crack propagation. Compression testing revealed up to 654 % and 186 % improvements in strength and modulus, respectively, with the optimal composite achieving a compressive strength of 121.5 MPa and modulus of 5.4 GPa, surpassing both monolithic silica and pure epoxy. Flexural strength and modulus increased by up to 360 % and 64 %, while fracture toughness improved five- to sixfold compared to solid silica. This enhanced performance was attributed to synergistic toughening originating from crack deflection, tablet pull-out, epoxy deformation, and sealing of surface cracks in the ceramic phase. The results demonstrate that AM-enabled bioinspired ceramic architectures, optimized sintering, and polymer infiltration provide a versatile route for fabricating lightweight ceramic–polymer composites with enhanced mechanical performance and design flexibility.