The strength of nanosize objects increases with decreasing size and can approximate the theoretical shear strength. We use dealloying for creating nanoporous materials that are networks of metallic nanoscale "ligaments". These materials can be made with macroscopic dimensions and can, in principle, be shaped into engineering components comprising in the order of 1014 ligaments per mm3. Nanoporous metals also offer new opportunities for materials design towards functionality. Throughout the pore space, the state of the metal surface can be reversibly modulated under control of electrical or chemical signals. This affords changes of the capillary forces and of the optical or chemical properties in the interfacial regions, strongly affecting the effective macroscopic materials behavior. So far we have addressed size‐dependent strength and elasticity, the impact of the surfaces for the mechanical behavior, and the role of the network topology. In the second funding period we aim to demonstrate materials that simultaneously bring interesting mechanical behavior and novel functionality. As one instance, we have shown that nanoporous gold‐based hybrid nanomaterials can exhibit an effective piezoelectric response. This is remarkable since piezoelectricity is classically restricted to ceramics.
H.-J. Jin, J. Weissmüller and D. Farkas
Mechanical response of nanoporous metals: A story of size, surface stress, and severed struts
MRS Bulletin 43, 35-42 (2018).
https://doi.org/10.1557/mrs.2017.302 (Project B2)
C. Soyarslan, S. Bargmann, M. Pradas and J. Weissmüller
3D stochastic bicontinuous microstructures: Generation, topology and elasticity
Acta Materialia 149, 326-340 (2018).
https://doi.org/10.1016/j.actamat.2018.01.005 open access (Project B2, B6)
S. Shi, J. Markmann and J. Weissmüller
Synthesis of uniform bulk nanoporous palladium with tunable structure
Electrochimica Acta 285, 60-69 (2018).
https://doi.org/10.1016/j.electacta.2018.07.081 open access (Project B2, B8)
G.Y. Gor, P. Huber and J. Weissmüller
Elastocapillarity in nanopores: Sorption strain from the actions of surface tension and surface stress
Phys. Rev. Materials 2, 086002 (2018).
https://doi.org/10.1103/PhysRevMaterials.2.086002 (Project B2, B7)
N. Mameka, L. Lührs, S. Heissler, H. Gliemann and C. Wöll
Tailoring the strength of nanoporous gold by self-assembled monolayers of alkanethiols
ACS Appl. Nano Mater. (2018).
https://doi.org/10.1021/acsanm.8b01368 (Projects B2, B8)
K. Wang, C. Hartig, M. Blankenburg, M. Müller, R. Günther and J. Weissmüller
Local flow stresses in interpenetrating-phase composites based on nanoporous gold - In situ diffraction
Scr. Mater. 127, 151-155 (2017). Abstract, PDF (OpenAccess) (Project B2, Z2)
K. Hu, M. Ziehmer, , W. Ke and E.T. Lilleodden
Nanoporous gold: 3D structural analyses of representative volumes and their implications on scaling relations of mechanical behaviour
Philos. Mag. DOI:10.1080/14786435.2016.1222087 (2016). Abstract, PDF (Project B2, B4)
M. Ziehmer, K. Hu, W. Ke and E.T. Lilleodden
A principle curvatures analysis of the isothermal evolution of nanoporous gold: Quantifying the characteristic length scales
Acta Materialia 120, 24-31 (2016). Abstract, PDF (OpenAcess) (Project B4, B2)
C. Stenner, L.-H. Shao, N. Mameka and J. Weissmüller
Piezoelectric gold - Strong charge-load response in a metal-based hybrid nanomaterial
Adv. Funct. Mater. DOI:10.1002/adfm.201600938 (2016). Abstract, PDF (OpenAccess) (Project B2)
B. Roschning and N. Huber
Scaling laws of nanoporous gold under uniaxial compression: Effects of structural disorder on the solid fraction, elastic Poisson's ratio, Young's modulus and yield strength
J. Mech. Phys. Solids 92, 55-71 (2016). Abstract, PDF (Open Access) (Projects B4, B2)
B.-N. D. Ngô, A. Stukowski, N. Mameka, J. Markmann, K. Albe and J. Weissmüller
Anomalous compliance and early yielding of nanoporous gold
Acta Materialia, DOI:10.1016/j.actamat.2015.04.021 (2015).
http://www.sciencedirect.com/science/article/pii/S1359645415002633 (Project B2)
K. Wang, A. Kobler, C. Kübel, H. Jelitto, G. Schneider and J. Weissmüller
Nanoporous-gold-based composites: towards tensile ductility
NPG Asia Mater. 7, e187, DOI:10.1038/am.2015.58 (2015).
http://www.nature.com/am/journal/v7/n6/full/am201558a.html (Projects B2, A6)
L. Lührs, C. Soyarslan, J. Markmann, S. Bargmann and J. Weissmüller
Elastic and plastic Poisson's ratios of nanoporous gold
Scripta Materialia, DOI:10.1016/j.scriptamat.2015.08.002 (2015).
http://www.sciencedirect.com/science/article/pii/S1359646215003486 (Projects B2, B6)
N. Mameka, K. Wang, J. Markmann, E.T. Lilleodden and J. Weissmüller
Nanoporous gold - Testing macro-scale samples to probe small-scale mechanical behavior
Mater. Res. Lett. DOI:10.1080/21663831.2015.1094679 (2015).
http://www.tandfonline.com/doi/abs/10.1080/21663831.2015.1094679 (Projects B2, B4) (open access)
B.A.M. Elsner, S. Müller, S. Bargmann and J. Weissmüller
Surface excess elasticity of gold: Ab initio coefficients and impact on the effective elastic response of nanowires
Acta Materialia 124, 468-477 (2017). www.sciencedirect.com/science/article/pii/S1359645416308436 (Projects B2, B3, B6)