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MM: Fachverband Metall- und Materialphysik

MM 40: Liquid and Amorphous Metals

MM 40.4: Vortrag

Donnerstag, 4. April 2019, 15:45–16:00, H46

Impact of cryogenic rejuvenation on calorimetric and kinetic properties of plastically deformed Pd₄₀Ni₄₀P₂₀ bulk metallic glass — •Afrouz Hassanpour, Sergiy V. Divinski, Martin Peterlechner, and Gerhard Wilde — Institute of Materials Physics University of Münster Wilhelm-Klemm-Str. 10 48149 Münster Germany

In metallic glasses, plastic deformation at ambient conditions is typically localized in shear bands. In the present work, the impact of different types of deformation, namely of high-pressure torsion (HPT) and cold rolling, and the effect of subsequent cryogenic rejuvenation are analyzed for the Pd₄₀Ni₄₀P₂₀ bulk metallic glass. Different experimental techniques are applied to examine the structural changes due to the plastic flow, including X-ray diffraction, differential scanning calorimetry and the radiotracer diffusion measurement. Using HPT processing, extremely large shear deformation is imposed under quasi-hydrostatic conditions. The plastic flow during deformation likely increases the excess free volume in the material and affects the local atomic configurations. We report on an increase of the diffusion rates in the deformed samples in comparison to the as-cast ones and the impact of cryogenic rejuvenation on the diffusion enhancement. Shear bands are shown to represent short-circuit paths for diffusion and their relaxation is discussed.