High strength metallic wood from nanostructured nickel inverse opal materials

Abstract

This paper describes a nickel-based cellular material, which has the strength of titanium and the density of water. The material’s strength arises from size-dependent strengthening of load-bearing nickel struts whose diameter is as small as 17 nm and whose 8 GPa yield strength exceeds that of bulk nickel by up to 4X. The mechanical properties of this material can be controlled by varying the nanometer-scale geometry, with strength varying over the range 90–880 MPa, modulus varying over the range 14–116 GPa, and density varying over the range 880–14500 kg/m3. We refer to this material as a “metallic wood,” because it has the high mechanical strength and chemical stability of metal, as well as a density close to that of natural materials such as wood.

Temperature-dependent mechanical behavior of three-dimensionally ordered macroporous tungsten

“…Because the constants for such a model should be functions only of the structure [43], the model seems applicable to the 3DOM W structure in this study. The model employed here was developed by Pikul et al using finite element simulations of Ni inverse opals assuming isotropic elasticity [20]:…”

“…Moreover, the densities of 3DOM materials can be reduced into the single-digit percentages relative to those of the bulk material [11]. Additional flexibility exists to produce nanoporous thin films and to employ a wide variety of materials (e.g., 3DOM materials have been generated from C [12], V 2 O 5 [13], SiO 2 [14,15], W and W-Mo [16,17,18], TiO 2 [11,19], Ni [20,21], Cu [22,23]). These geometries and chemistries are not all readily produced with electrochemical dealloying processes.…”

“…Some of the materials that have been synthesized in the 3DOM structure do not typically deform via thermally activated mechanisms. These include face-centered cubic (FCC) metals [20,21,22,23], which deform by dislocationmediated processes on close-packed planes and directions, and ceramics [11,14,15,19], which demonstrate limited plasticity at experimentally accessible temperatures. In contrast, body-centered cubic (BCC) metals are known to possess highly temperature-dependent mechanical properties due to increasing numbers of active slip systems ({110},{112}, and {123}) at increasing temperatures [24].…”

Low‐Energy Room‐Temperature Healing of Cellular Metals

“…Future work can explore repeated healing and encapsulating electrolyte into the cellular material for a fully integrated and healable structural material, but difficulties may arise from the mass penalty imposed by the electrolyte and the need to prevent electrolyte leakage. Our transport‐mediated approach can be applied to increase lifetime, reduce weight, and prevent premature failure of cellular metals, which are widely used in structural materials with high strength, high stiffness, and low weight . Additionally, this work presents a new approach to heal electrically and thermally conductive materials, and will benefit from advances in 3D printing, self‐healing polymers, and topology optimization tools.…”

“…In this work, we use electrochemical transport of nickel in polymer‐coated cellular nickel materials to demonstrate rapid, effective, and low‐energy healing of metal at room temperature. We chose cellular nickel because of its wide use, electrochemical reversibility, and demonstrated light weight and high strength . The polymer coating enabled selective healing only at fractured locations.…”