Berlin 2018 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 34: Nanomaterials
MM 34.3: Vortrag
Mittwoch, 14. März 2018, 12:15–12:30, H 0106
A Live Broadcast From Within Deforming Nanocrystalline PdAu Aggregates — •Michael Johannes Deckarm1, Andreas Leibner1, Marta Majkut2, Vadim Dyadkin2, and Rainer Birringer1 — 1Saarland University, D-66123 Saarbrücken — 2ESRF, F-38043 Grenoble Cedex 9
Scaling the grain size of PdAu down to the low end of the nano scale (≈ 10nm) entails a dramatic change in mechanical properties. In a recent study, Grewer et al. [1] examined the deformation of nanocrystalline PdAu in an in-situ experiment using a combination of optical strain and synchrotron-based X-ray diffraction measurement. The central result was a quantitative estimate of the contributions of various processes to the deformation. In continuation of this work, we explored the effects of different strain rates and stress states, respectively, by a series of experiments at beamline ID11 at the ESRF. Scattering data with high temporal resolution spanning the entire deformation provide us with a broadcast of the evolving stress state. Specifically, we discuss a whole powder pattern modelling approach to extract structural information from our scattering data [2], to then reconstruct average stress and strain states of differently oriented grains as well as the signature of the elastic anisotropy of PdAu crystallites and its relation to the stresses or strains arising from the compatibility constraints in nanocrystalline PdAu aggregate.
[1] M. Grewer et al., Mechanics of Materials, 114, 2017, 254-267 [2] Scardi, P; Leoni, M., Acta crystallographica. Section A, Foundations of crystallography., 57., 2001, 604-613.