Berlin 2018 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 41: Liquid and Amorphous Metals

MM 41.6: Vortrag

Mittwoch, 14. März 2018, 16:30–16:45, TC 010

Low temperature excess heat capacity of AlYFe metallic glasses — •Marius Gerlitz, René Hubek, Martin Peterlechner, Harald Rösner, and Gerhard Wilde — Institute of Materials Physics, University of Münster

The deformation behavior of metallic glasses differs from their crystalline counterpart due to the absence of defects like dislocations. Metallic glasses deform at ambient temperatures typically by nanometer sized, localized shear bands. To what extend a change in the structure of the surrounding matrix contributes to the plastic deformation is under current investigation. The vibrational states of atoms depend on their bonding and consequently on their mechanical coupling. Thus, low temperature specific heat measurements are well suited to understand fundamental characteristics of vibrational modes. The excessive contribution to the specific heat at low temperatures, known as the boson peak, is a distinct feature in glasses and is though as being closely related to the structural states that allow for unit shear events. This work focuses on AlYFe as a representative of marginally glass forming systems. Deformed and relaxed sample states were analyzed by heat capacity measurements, X-ray-diffraction, calorimetric measurements as well as electron microscopy. The results are discussed with respect to the present literature on the boson peak. An enhanced relaxation behavior of metallic glasses is observed in deformed samples. The matrix is stated to be involved in the relaxation process.