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.