Dynamic compressive response and impact resistance of bioinspired nacre-like 2024Al/B₄C composites

In this study, the researchers constructed nacre-inspired 2024Al/B₄C composites with a lamellar-interpenetrated structure using pressured infiltration of alloy melt into freeze-cast B₄C scaffolds, and investigated their dynamic and ballistic properties. The defects such as pores or cracks were hardly observed, and a few intermetallic compounds (IMCs) were contained within the alloy matrix. Because of strain-rate hardening and alloy matrix melting, the dynamic compressive strength and strain were greater than quasi-static ones. The dynamic response could be interpreted by a mixture rule according to B₄C volume fraction, and by main fracture phenomena such as cracking of B₄C and IMCs, alloy matrix deformation, and interfacial debonding. After the ballistic test, the nacre-like composites achieved enhanced impact resistance compared to conventional Al/B₄C materials, while maintaining integrity rather than breaking destructively as monolithic Al/B₄C composites did, which derived from multiple energy absorption mechanisms including crack deflection, ductile-ligament bridging, and pull-out behavior. This work opens a promising new avenue for the development of advanced armor systems.