Dynamic cryo-mechanical properties of additively manufactured nanocrystalline nickel 3D microarchitectures. (August 2022)

• Record Type: Journal Article
• Authors: Schwiedrzik, Jakob; Ramachandramoorthy, Rajaprakash; Edwards, Thomas E.J.; Schürch, Patrik; Casari, Daniele; Duarte, Maria J.; Mohanty, Gaurav; Dehm, Gerhard; Maeder, Xavier; Philippe, Laetitia; Breguet, Jean-Marc; Michler, Johann
• Is Part Of: Materials & design. Volume 220(2022)
• Publication Date: 2022-08
• Subjects: Nanocrystalline nickel -- Micromechanics -- Cryogenic temperature -- High strain rate -- Microlattices; MEMS Micro electro-mechanical system -- TAE Template-assisted electrodeposition -- FIB Focused ion beam -- APT Atom probe tomography -- TKD Transmission Kikuchi diffraction -- XRD X-ray diffraction -- FEM Finite element method -- SEM Scanning electron microscope -- TEM Transmission electron microscope -- EBSD Electron backscatter diffraction -- HAGB High angle grain boundary -- LAGB Low angle grain boundary -- TB Twin boundary -- PDMP Partial dislocation mediated process -- SFE Stacking fault energy -- CTB Coherent twin boundary -- KUBC Kinematic uniform boundary condition; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2022.110836
• Languages: English
• ISSNs: 0264-1275

Abstract

Graphical abstract: Highlights: Metal micropillars were synthesized by template-assisted electrodeposition. Mechanical testing was performed at cryogenic temperatures and high strain rates. Structure-property relationships were identified for a large range of conditions. The deformation mechanism was identified to be collective dislocation nucleation. 3D Microlattices showcase the promise of the method for complex microarchitectures. Abstract: Template-assisted electrodeposition is a promising microscale additive manufacturing technique allowing to deposit pure metals with high resolution. To allow the application-relevant design of metamaterials, it is necessary to establish microstructure-mechanical property relationships under extreme conditions. In this work, a novel process based on two-photon lithography was used to synthesize arrays of nanocrystalline nickel micropillars and complex microlattices. This allowed high throughput mechanical testing using a newly developed in situ nanoindenter at unprecedented combination of cryogenic temperatures (160 to 300 K) and strain rates (0.001 to 500 s −1 ). Strain rate sensitivity was found to increase from ∼ 0.004 at 300 K to ∼ 0.008 at 160 K. Thermal activation analysis showed a decrease in activation volume from 122b 3 at 300 K to 45b 3 at 160 K and an activation energy of 0.59 eV in line with collective dislocation nucleation as the rate limiting mechanism. Transmission Kikuchi Diffraction allowed quantifying microstructural changes during deformation. As such, a deformation map along with the responsible deformation mechanisms has been ascertained for additively micromanufactured nanocrystalline nickel at unique combinations of extreme temperatures and strain rates. Further, rate-dependent compression of microlattices and complementary finite element simulations using the results from micropillars as constitutive models exemplified the promise of such metal microarchitectures in space and aviation applications.