Additive manufacturing of bionic layered ceramic-metal composites for enhanced toughness and damage resistance

Specific combinations of different materials, interfacial geometries, gradations, and layering in crysomallon squamiferum (CS) shells contribute to their excellent damage resistance. The tortoise shell occlusal joints also exhibit a wide range of resistance to damage due to their unique occlusal structure. Herein, bionic tortoiseshell occlusion suture structures of various materials were printed using two additive manufacturing (AM) techniques: vat photopolymerization (VPP) and powder bed fusion (PBF). CS bionic composites were prepared through polymer infiltration, leveraging the capabilities of AM. The simple and flexible production successfully overcomes challenges associated with fabricating complex bionic structures. The microstructure and surface bonding of the composites were analysed by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Additionally, finite element method (FEM) and molecular dynamics (MD) simulations were performed. Results demonstrate that the composites exhibit excellent mechanical performance, with 41.79% increase in flexural strength, 41.83% increase in fracture toughness, and 554.94% increase in work of fracture compared to normal layered ceramic composites.