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MM: Fachverband Metall- und Materialphysik

MM 39: Liquid and Amorphous Metals I - Shearbands

MM 39.2: Talk

Wednesday, April 2, 2014, 10:30–10:45, IFW A

Mechanical analysis of amorphous solids with large amplitude oscillatory spectroscopy (LAOS) — •Stefanie Finkhäuser¹, Ranko Richert², Carsten Mahn¹, and Konrad Samwer¹ — ¹1.Physikalisches Institut, Georg-August Universität Göttingen — ²Department of Chemistry & Biochemistry, Arizona State University

In the presence of mechanical fields, glassy materials are known to reveal many interesting phenomena. One of them is a crossover from a linear behavior in stress-strain dependency to a nonlinear behavior. To investigate this crossover in detail, we use dynamic mechanical excitation with large amplitudes. The sample is excited with a sinusoidal stress whose amplitude is large enough to lead to nonlinear strain-responses. The Fourier-analysis of these nonlinear responses contains higher harmonic contributions. These can give further insight into interactions among local plastic events, which lead to the nonlinear response. By switching between large amplitudes and small amplitudes which give a linear strain-response, the time dependence of these interactions is investigated. We will show results on PMMA and bulk metallic glasses.

Financial support by the DFG SFB 937 is thankfully acknowledged.