Bio-inspired material-structure-function integrated additive manufacturing of Al-based metamaterials with surpassing energy absorption

Additively manufactured mechanical metamaterials exhibit extraordinary physical and mechanical performance. However, achieving a balance between lightweight design, strength, and energy absorption remains challenging. Here, we develop a material-structure-function integrated strategy to additively manufacture lightweight metamaterials. Specifically, strong yet ductile aluminum (Al) alloy with heterogeneous grain was developed to print hero shrew-inspired damage-resistant metamaterials. The synergistic interplay between microscale strengthening and mesoscale architectural stress regulation leads to a cross-scale coordination mechanism, which effectively bridges material heterogeneities and structural hierarchy for multilevel energy dissipation. Such a strategy enables our metamaterials to maintain a stable stress platform during deformation. Hence, our metamaterials display an excellent combination of ultralightweight (0.91 ± 0.01 g/cm³), high relative yield strength (17.0 ± 0.7%), and unprecedented specific energy absorption (39.1 ± 0.7 J/g), surpassing most metallic metamaterials. This facile concept expands the design space for lightweight metamaterials and demonstrates scalable strategies to realize the cross-scale coordination mechanism required by multifunction, showing transformative potential in mass production for sustainable engineering solutions.