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

Abstract

Abstract

Introduction - Porous Metals: From Nano to Macro

“…"Porous metalsfrom nano to macro": figures reproduced from articles in this Focus Issue illustrate the range of pore size in porous metals. (a) scanning transmission electron micrograph of a nanoporous palladium -polymer composite membranes for separations and catalysis; the nanoporous Pd was prepared by the dealloying method 20 , (b) scanning electron microscope (SEM) micrograph of nanoporous copper prepared by dealloying 21 , (c) molecular dynamics simulations of crystalline copper nanoporous structures during tensile loading22 scale is provided by individual atoms visible in enlarged view in circles, (d) SEM micrograph of tensile section of a carbon nanotubes reinforced aluminum foam prepared by powder metallurgy23 (e) three-dimensionally ordered porous tungsten (inverse opals structure), prepared by a templating method24 (f) tomographic view of porous iron created by freeze casting, ice template removal and sintering25 (g) a 3D printed Ti-6Al-4V gyroid-structured scaffold showing diagonal shear bands from compression tests 26 (h) X-ray tomographic reconstruction of open-channel aluminum fabricated by casting and subsequent extraction of lubricated metallic wires27 28 (i) photographs of closed-cell aluminum foams with graded density before and after a compression test29 ( j) SEM micrographs of hierarchically-porous titanium with macro-/micro-/nanopores, prepared using NaCl spacer and dealloying methods30 .Introduction ▪ Journal of Materials Research…”

3D Periodic and Interpenetrating Tungsten–Silicon Oxycarbide Nanocomposites Designed for Mechanical Robustness

“…Polymethyl methacrylate (PMMA) spheres with average diameters of 397 ± 4 nm were synthesized by emulsifier-free emulsion polymerization following established methods . The PMMA spheres were then assembled into colloidal crystals in the form of thin films by convective self-assembly, following a previously reported method . The detailed steps for assembling the PMMA colloidal crystal films are provided in the Supporting Information.…”

“…3DOM W was synthesized following a previously reported method: a water/methanol solution (4:1 in volume) of 1 M acetylated peroxotungstic acid was used to infiltrate the PMMA colloidal crystal template, followed by heat treatment under H 2 (2 °C/min to 310 °C, dwelling at 310 °C for 2 h, then 5 °C/min to 800 °C, and dwelling at 800 °C for 1 h). , The PMMA template was removed during the heat treatment and 3DOM W was formed. The 3DOM W product was in the form of thin, strip-like pieces with a flat surface.…”

“…3DOM materials are porous solids that feature a highly ordered, fully interconnected, and periodic porous structure with uniform pore sizes, typically a few hundred nanometers in diameter. , 3DOM materials have been extensively studied, and they have been created in a wide variety of compositions, , such as carbon, ceramics (SiO 2 , MgO, Cr 2 O 3 , Fe 2 O 3 , ZrO 2 ), metals, and metal alloys (W, WMo, Mn 3 Co 7 , Ni x Co 1– x ). , The mechanical properties of 3DOM materials have drawn attention recently. Having ordered and periodic structures with nanosized ligaments, 3DOM materials in certain compositions have exhibited high strength. − For example, Pikul et al demonstrated that 3DOM Ni with skeletal grains having a size of ∼15 nm has a yield strength that exceeds that of bulk Ni by a factor of more than 4 because the ligaments become nanostructured . When a 3DOM material is used as the scaffold, another component can be introduced into the interconnected voids to form an IPC type nanocomposite.…”

“…Tungsten, a body-centered cubic metal, was selected in part because it undergoes a brittle–ductile transition (BDT) in the temperature range 100–200 °C . Notably, large increases in deformability have been observed in 3DOM W when the temperature was increased to 225 °C . This behavior facilitates mechanical characterization when both phases are brittle at room temperature as well as when the tungsten exhibits increased plasticity at moderately elevated temperatures.…”