Fabrication and characterization of alumina-copper composites with complex bioinspired microstructures

Natural organisms are a rich source of inspiration for designing bioinspired microstructures that can be integrated into composites to achieve tunable mechanical performance. However, the inclusion of such structural motifs has been limited to a few structures only due to the processing limitations, but the current advancements in composite manufacturing processing such as magnetically assisted slip casting (MASC) in conjunction with pressureless sintering have enabled the precise creation of complex microstructures in ceramic-metal (CM) composites. Here, we produced bioinspired Al 2 O 3 -Cu composites with five distinct microstructures, inspired from molluscs, conch shells, mantis shrimp's dactyl club and a combination of crab and molluscs, and systemically investigated the responses under different loading conditions. The nacre-like brick-and-mortar microstructured and herringbone microstructured CM composites exhibited the highest flexural and compressive strengths, whereas the Bouligand microstructured composites demonstrated the greatest crack growth toughness. The zigzag arrangement in the herringbone microstructured CM composites achieved the highest energy dissipation by damping, while the Bouligand and the crosslamellar microstructured composites exhibited the lowest damping response but the highest energy absorption during impact due to their twisted microstructures. These findings provide valuable insights into the structure-property correlations in bioinspired CM composites and establish a framework for tailoring mechanical performance through controlled microstructural design.