10.15480/882.1637
Elsner, Beatrix A. M.
Beatrix A. M.
Elsner
0000-0003-4244-1886
1159408998
Müller, Stefan
Stefan
Müller
115941078X
Bargmann, Swantje
Swantje
Bargmann
0000-0001-7403-7066
136307426
Weissmüller, Jörg
Jörg
Weissmüller
0000-0002-8958-4414
1051291577
Surface excess elasticity of gold: ab initio coefficients and impact on the effective elastic response of nanowires
Elsevier
2016
surface excess elastic parameters
surface lamé constants
nanoelasticity
nanowire
density functional theory
Ingenieurwissenschaften
TUHH Universitätsbibliothek
TUHH Universitätsbibliothek
2018-05-11
2018-05-11
2016-11-20
en
Journal Article
Acta Materialia (124): 468-477 (2017)
http://tubdok.tub.tuhh.de/handle/11420/1640
urn:nbn:de:gbv:830-88220650
10.15480/882.1637
11420/1640
10.1016/j.actamat.2016.10.066
https://creativecommons.org/licenses/by-nc-nd/4.0/
Predicting the influence of the surface on the effective elastic properties of nanoscale structures and nanomaterials remains a challenge, which we here address on both levels, continuum and atomic. Density Functional Theory (DFT) computation at the atomic level yields the first reliable surface excess elastic parameters for the (111) and (001) surfaces of gold. At the continuum level, we derive closed-form expressions for the effective elastic behavior that can be combined with the DFT-derived excess elastic parameters to obtain the effective axial, torsion, and bending stiffness of circular nanowires with surface excess elasticity. The two approaches use different reference frames, and we emphasize the need for consistent stress definitions and for conversion between the separate stress measures when transferring results between the approaches. We present excess elastic parameters separately for Cauchy and 2nd Piola-Kirchhoff stresses, demonstrating that the conversion substantially modifies their numerical value and may even invert their sign. The results afford an assessment of the contribution of the surface excess elastic parameters to the effective elastic response of nanoscale beams or wires. This assessment sheds doubt on earlier suggestions relating experimental observations of an effective stiffening or softening at small size to the excess elasticity of clean surfaces.
Deutsche Forschungsgemeinschaft (DFG)
https://doi.org/10.13039/501100001659
192346071
SFB 986: Teilprojekt B2 - Feste und leichte Hybridwerkstoffe auf Basis nanoporöser Metalle
1359-6454
Acta materialia
2016
Elsevier