Berlin 2015 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 52: Nanomaterials III: Nanoporous Gold and Phase Transformations
MM 52.2: Vortrag
Donnerstag, 19. März 2015, 12:00–12:15, H 0106
Investigation of the Deformation Behavior of Nanoporous Metals Using Digital Image Correlation — •Lukas Lührs1, Jürgen Markmann1,2, and Jörg Weissmüller1,2 — 1Institut für Werkstoffphysik und -technologie, Technische Universität Hamburg-Harburg — 2Institut für Werkstoffforschung, Werkstoffmechanik, Helmholtz-Zentrum Geesthacht
Nanoporous metals have an extremely high specific surface area. This makes them of interest for studies of small-scale deformation, since the mechanical behavior can be manipulated through number and properties of the surfaces. A fundamental issue in elastic as well as plastic deformation of nanoporous metals is the transverse coupling, in other words, the link between longitudinal and transverse strain under uniaxial loading conditions. Millimeter sized nanoporous gold samples with different ligament size were prepared via dealloying and tested mechanically under single and cyclic compression up to strains of 50%. By using a digital image correlation set-up, 2-dimensionally resolved strain measurements of the sample surface could be obtained, enabled by full field displacement calculations upon loading. Among other material properties, the development of the elastic and plastic Poisson’s ratio during the deformation process was determined. In each instance the lateral deformation is small. Yet, the transverse coupling does not vanish; this is contrary to some previously published claims. Furthermore, a significant dependence of the Poisson’s ratio on the ligament size as well as the macroscopic strain was observed.