Multiscale metallic metamaterials

Abstract

Materials with three-dimensional micro- and nanoarchitectures exhibit many beneficial mechanical, energy conversion and optical properties. However, these three-dimensional microarchitectures are significantly limited by their scalability. Efforts have only been successful only in demonstrating overall structure sizes of hundreds of micrometres, or contain size-scale gaps of several orders of magnitude. This results in degraded mechanical properties at the macroscale. Here we demonstrate hierarchical metamaterials with disparate three-dimensional features spanning seven orders of magnitude, from nanometres to centimetres. At the macroscale they achieve high tensile elasticity (>20%) not found in their brittle-like metallic constituents, and a near-constant specific strength. Creation of these materials is enabled by a high-resolution, large-area additive manufacturing technique with scalability not achievable by two-photon polymerization or traditional stereolithography. With overall part sizes approaching tens of centimetres, these unique nanostructured metamaterials might find use in a broad array of applications.

Reexamining the mechanical property space of three-dimensional lattice architectures

“…These materials are 3D assemblies of beams with micro-and nanoscale constituent dimensions, and it is the confluence of nanometer-sized dimensions and architecture that gives rise to their unique properties [1][2][3]15,[18][19][20][21][22][23][24][25][26]. The theoretical maximum Young's modulus ‫)ܧ(‬ and yield strength (ߪ ௬ ) of a lightweight porous material are set by the Voigt bound, which are functions of the relative density (ߩ̅ ) as ‫ܧ‬ = ‫ܧ‬ ௦ ߩ̅ and ߪ ௬ = ߪ ௬௦ ߩ̅ .…”

“…Experimental and theoretical work on lattices have shown mixed results on the exact role of topology in governing strength and modulus scaling; a wide range of reported strength and stiffness power law scaling relationships exists, even for topologically identical systems, and no experimentally realized M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 3 lightweight lattice matches the performance predicted by the Gurtner-Durand bound [1,2,18,[21][22][23]37,38].…”

High‐Entropy Alloy (HEA)‐Coated Nanolattice Structures and Their Mechanical Properties

“…[12,34] By altering the design and material composition of these micro/nano-lattices, it is possible to produce a wide variety of materials with unprecedented properties that defies traditional mechanics, such as a strong, yet lightweight materials. [35,36] Rationally combining sputtering technique in preparation of HEA with TPL will possibly open an entirely new field of materials, which has the potential to reach theoretical limits and applications across multiple disciplines that would otherwise be impossible with macroscopic constructions.…”

Architected cellular ceramics with tailored stiffness via direct foam writing

“…Recently, multiscale metamaterials with properties heretofore unseen in engineered materials have been created by light-based 3D printing of photopolymerizable organic (16)(17)(18)(19)(20)(21) and preceramic resins (22). Specifically, microlattices, octet structures, and tetrakaidecahedra with struts composed of hollow shells (16)(17)(18)20), solid features (21,22), or even finer trusses (16,19) have been produced, which may exhibit bending, stretching, or mixed mode mechanical responses. However, these lattices are limited to open architectures constructed using photopolymerizable materials that must be subsequently transformed to ceramic or metal through some combination of coating and pyrolysis.…”