Though beam-based lattices have dominated mechanical metamaterials for the past two decades, low structural efficiency limits their performance to fractions of the Hashin-Shtrikman and Suquet upper bounds, i.e. the theoretical stiffness and strength limits of any isotropic cellular topology, respectively. While plate-based designs are predicted to reach the upper bounds, experimental verification has remained elusive due to significant manufacturing challenges. Here, we present a new class of nanolattices, constructed from closedcell plate-architectures. Carbon plate-nanolattices are fabricated via two-photon lithography and pyrolysis and shown to reach the Hashin-Shtrikman and Suquet upper bounds, via in situ mechanical compression, nano-computed tomography and micro-Raman spectroscopy. Demonstrating specific strengths surpassing those of bulk diamond and average performance improvements up to 639% over the best beam-nanolattices, this study provides detailed experimental evidence of plate architectures as a superior mechanical metamaterial topology.

Ductile high-strength ceramics would be ideal for many structural applications; however, they have been neither demonstrated at dimensions much above the nanoscale nor shown to be manufacturable with application-relevant processes. Here, we present a robust route to additively manufacture ductile, ultrastrong silicon oxycarbide nanoceramics via two-photon polymerization of a preceramic resin and subsequent pyrolysis. We measure plastic deformability with strains up to 25% and strengths >7 GPa for 20-mm specimens, opening up potential for fabrication of mesoscale ductile ceramic components.

Failure of materials and structures is inherently linked to localized mechanisms, from shear banding in metals, to crack propagation in ceramics and collapse of space‐trusses after buckling of individual struts. In lightweight structures, localized deformation causes catastrophic failure, limiting their application to small strain regimes. To ensure robustness under real‐world nonlinear loading scenarios, overdesigned linear‐elastic constructions are adopted. Here, the concept of delocalized deformation as a pathway to failure‐resistant structures and materials is introduced. Space‐tileable tensegrity metamaterials achieving delocalized deformation via the discontinuity of their compression members are presented. Unprecedented failure resistance is shown, with up to 25‐fold enhancement in deformability and orders of magnitude increased energy absorption capability without failure over same‐strength state‐of‐the‐art lattice architectures. This study provides important groundwork for design of superior engineering systems, from reusable impact protection systems to adaptive load‐bearing structures.