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The indentation response of Nickel nano double gyroid lattices

Accepted version
Peer-reviewed

Type

Article

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Authors

Khaderi, SN 
Scherer, MRJ 
Hall, CE 
Steiner, U 
Ramamurty, U 

Abstract

The indentation response of Nickel nano double gyroid films has been measured using a Berkovich nanoindenter and the effective mechanical properties of the Ni double gyroid lattices inferred via a multi-scale finite element analysis. The 1μm thick double gyroid films were manufactured by block copolymer self-assembly followed by electrodeposition of the Ni resulting in two interpenetrating single gyroids of opposite chirality, an overall relative density of 38% and a cell size of about 45 nm. The measured hardness was ∼0.6 GPa with no discernable indentation size effect. A multi-scale finite element (FE) analysis revealed that the uniaxial compressive strength is approximately equal to the hardness for this compressible lattice. Thus, the 38% relative density Ni double gyroid has a strength equal to or greater than the strongest fully dense bulk Ni alloys. The FE calculations revealed that this was a consequence of that fact that the Ni in the 13 nm gyroid struts was essentially dislocation free and had a strength of about 5.7 GPa, i.e. approaching the theoretical strength value of Ni. The measurements and calculations reported here suggest that in spite of the nano gyroids having a bending-dominated topology they attain strengths higher than those reported for stretching-dominated micron scale lattice materials made via 3D printing. We thus argue that relatively fast and easy self-assembly processes are a competitive alternative to 3D printing manufacture methods for making high strength lattice materials.

Description

Keywords

Lattice materials, nano-lattices, Size effects, Indentation

Journal Title

Extreme Mechanics Letters

Conference Name

Journal ISSN

2352-4316
2352-4316

Volume Title

10

Publisher

Elsevier BV
Sponsorship
University of Virginia (GG11379-136860)
European Commission Horizon 2020 (H2020) ERC (206409)
EPSRC (EP/M015211/1)
Engineering and Physical Sciences Research Council (EP/M015211/1)