Nanomechanical behaviour of open-cell nanoporous metals: homogeneous versus thickness-dependent porosity
Esqué-de los Ojos, Daniel (Universitat Autònoma de Barcelona. Departament de Física)
Zhang, Jin (Universitat Autònoma de Barcelona. Departament de Física)
Fornell Beringues, Jordina (Universitat Autònoma de Barcelona. Departament de Física)
Pellicer Vilà, Eva Maria (Universitat Autònoma de Barcelona. Departament de Física)
Sort Viñas, Jordi (Institució Catalana de Recerca i Estudis Avançats)

Date:	2016
Abstract:	Two dierent nanoporous materials, porous copper prepared by dealloying and porous nickel prepared by electrodeposition, have been studied by means of nanoindentation experiments at dierent maximum applied loads. While nanoporous Cu is homogeneous along its cross-section, the electrodeposited Ni lms show a graded porosity, with smaller pores and thicker pore walls close to the lm's surface. The mechanical properties of the two materials have been extracted using a methodology based on scaling laws and subsequent interpretation has been performed using nite element simulations. Two dierent deformation mechanisms are observed for nanoporous Cu and nanoporous Ni, respectively. Dealloyed porous copper behaves as an homogeneous material without evident eect of densication and with mechanical properties that are independent of the applied load. Given this homogeneity, it is possible to t the entire loading - unloading curve for dierent maximum applied loads with a single set of mechanical properties. Conversely, electrodeposited porous nickel shows a decrease in the reduced Young's modulus, an increase in yield stress and a constant hardness when the maximum applied load during nanoindentation is increased. While the decrease in the reduced Young's modulus can be explained in the context of thickness inhomogeneity of the electrodeposited porous nickel (i. e. , increase of porosity with depth), this cannot explain, and actually would go against, the observed increase in the yield stress, which is instead associated to the decrease in the ligament size.
Grants:	Ministerio de Economía y Competitividad RYC-2012-10839 Agència de Gestió d'Ajuts Universitaris i de Recerca 2014/SGR-1015 European Commission 648454
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, i la comunicació pública de l'obra, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original. No es permet la creació d'obres derivades.
Language:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Subject:	Dealloying ; Electrodeposition ; Finite element analysis (FEA) ; Mechancial properties ; Nanoindentation ; Porous materials ; Size eects
Published in:	Mechanics of Materials, Vol. 100 (Setembre 2016) , p. 167-174, ISSN 0167-6636

DOI: 10.1016/j.mechmat.2016.06.014

Postprint 15 p, 1.1 MB

The record appears in these collections:
Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > Group of Smart Nanoengineered Materials, Nanomechanics and Nanomagnetism (Gnm3) > SPIN-PORICS
Articles > Research articles
Articles > Published articles