title: Multiscale hierarchical assembly strategy and mechanical prowess in conch shells (Busycon carica).
abstract: Seashells are natural body armors with superior mechanical strength and ultra-high toughness compared with their major constituent counterparts. What building blocks and architecture render seashells such mechanical prowess? In this study, micro/nanoscale structural and mechanical characterization of conch shells (Busycon carica) has been carried out. Here we show direct evidence that the previously claimed single-crystal third-order lamellae--the basic building blocks in conch shells are essentially assembled with aragonite nanoparticles of the size ranging from 20 to 45 nm. The nanoparticle-constructed third-order lamellae are not brittle, but ductile. The three-order crossed-lamellar architecture interlocks cracks via crack deflection along the interfaces in a three-dimensional manner, thus confining the damage in a small region. The findings advance the understanding of the mystery of conch shell's mechanical robustness, provide additional design guidelines for developing bioinspired nanomaterials, and lay a constitutive foundation for modeling the deformation behavior of seashells.
authors.affiliation: Department of Mechanical Engineering, University of South Carolina, 300 Main Street, Columbia, SC 29208, USA.
authors.forename: Haoze
authors.initials: H
authors.lastname: Li
authors.forename: Zhi-Hui
authors.initials: ZH
authors.lastname: Xu
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Li
mesh_terms: D060105:Animal Shells / Q000737:chemistry* / Q000648:ultrastructure*; D000818:Animals; D002119:Calcium Carbonate; D049851:Gastropoda; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D053758:Nanoparticles
chemical_list: D002119:Calcium Carbonate
keywords: Conch shell; Ductility; Fracture toughness; Hierarchical structure; Nanoparticles assembly