Bioinspired hierarchical Al2O3/Al laminated composite fabricated by flake powder metallurgy

Inspired by nacre's design principle, a bottom-up strategy by self-assembly alignment of flake powders, namely flake powder metallurgy, is employed to fabricate bioinspired laminated composites with brick-and-mortar structure. The microscale flake Al2O3 powders and flake Al powders with native Al2O3 nanolayers are utilized to fabricate the bioinspired hierarchical Al2O3/Al laminated composites, and the composites with 5 vol% Al2O3 achieves an enhancement of 22% in strength with only a 7% compromise on ductility, leading to a notable improvement in toughness (17%) compared to the corresponding Al matrix. The higher strain hardening due to enhanced dislocation accumulation capacity at hierarchical Al2O3/Al interface can delay the occurrence of necking, and the large elongation after peak stress is attributed to multiple extrinsic toughening effect from brick and-mortar structure. The bottom-up strategy can guide the design and fabrication of advanced bioinspired laminated composites to achieve enhanced mechanical performance.