Catastrophic vs Gradual Collapse of Thin-Walled Nanocrystalline Ni Hollow Cylinders As Building Blocks of Microlattice Structures

Abstract

Catastrophic vs. gradual collapse of thin-walled nanocrystalline Ni hollow cylinders as building blocks of micro-lattice structures Supporting Information Mechanical Testing Two series of hollow cylinders with different wall thickness were prepared for uniaxial compression tests. For the first set (thick series), the wall thickness was ~ 400-600 nm, the diameter was 45-50 m, and the height ranged from 31 to 64 m. In the second set (thin series), the wall thickness was ~150 nm, with a diameter of ~30 m and length of 39 m. Uniaxial compression tests on the thick structures were performed in the XP

Microlattices as architected thin films: Analysis of mechanical properties and high strain elastic recovery

“…After postcuring at 120 o C in air for 12 h, the polymer microlattices were used as direct templates for deposition of thin films. Nickel and copper were deposited by electroless plating using a commercially available process (OM Group Inc., Cleveland, OH), which resulted in a nanocrystalline microstructure of nickel with 7 wt.% phosphorous with a grain size of 7 nm 20 and pure copper with a grain size of ∼10 nm, respectively, 21 see Ref. 1 for details.…”

Design, Fabrication, and Mechanics of 3D Micro‐/Nanolattices

“…Two distinct failure modes were observed: gradual collapse via local buckling and fracturing in the 150 nm cylinders and sudden catastrophic brittle collapse in the 500 nm cylinders . The theoretical critical buckling stress for 500 nm thick samples is ≈2.3–5.7 times higher than the experimental measurements, which is related to the different boundary conditions . However, for the 150 nm thick samples, the buckling stress is ≈99% lower than the predicted critical stress, which is attributed to the influence of the wall thickness on local buckling and fracturing .…”

“…In situ SEM compressive tests were recently conducted on nanocrystalline Ni hollow cylinders with wall thicknesses of 150 and 500 nm, which are basic building blocks for microlattices . Two distinct failure modes were observed: gradual collapse via local buckling and fracturing in the 150 nm cylinders and sudden catastrophic brittle collapse in the 500 nm cylinders . The theoretical critical buckling stress for 500 nm thick samples is ≈2.3–5.7 times higher than the experimental measurements, which is related to the different boundary conditions .…”

“…In alumina octet nanolattices, the failure transitions from elastic shell buckling to brittle fracturing of the material with an increase of ( t / R ) cr from 0.0161 to 0.0262 . In situ SEM compressive tests were recently conducted on nanocrystalline Ni hollow cylinders with wall thicknesses of 150 and 500 nm, which are basic building blocks for microlattices . Two distinct failure modes were observed: gradual collapse via local buckling and fracturing in the 150 nm cylinders and sudden catastrophic brittle collapse in the 500 nm cylinders .…”

Fabrication of 3D Micro-Architected/Nano-Architected Materials

“…A new scalable technique, based on self-propagating photopolymer waveguide (SPPW) polymerization followed by thin film deposition and etching of the polymeric substrate, was recently demonstrated; this technique allows rapid fabrication of cellular materials with extreme dimensional bandwidth (from 100 nm to 0.1-1 m), although it is limited to fairly simple lattice topologies [6]. These materials were shown to possess unique mechanical properties, by virtue of their extreme hierarchy and plasticity size effects (see Sections 3 and 5) [6][7][8][9].…”