Dresden 2017 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 66: Topical session: Dynamics, relaxation and deformation in deeply supercooled metallic liquids and glasses VI - mechanical properties

MM 66.2: Talk

Thursday, March 23, 2017, 16:15–16:30, IFW A

Mechanical properties of Palladium based bulk metallic glasses during deformation — •Niklas Nollmann, Vitalij Hieronymus-Schmidt, Isabelle Binkowski, Harald Rösner, and Gerhard Wilde — Universität Münster

Deformation of bulk metallic glasses (BMGs) at low temperatures and high stresses lead to an inhomogeneous plastic flow. During this plastic deformation the strain is localized in so called shear bands. Bulk metallic glasses show almost no ductility and fail alongside shear bands where the strain is localized. In our study we investigated PdNiP based glasses. PdNiP samples were deformed by cold rolling in several steps and the wave velocity was measured with an ultrasonic device after each step. Thus the dependence of the Poisson's ratio on the deformation state was observed. We also analyzed modifications of the mechanical properties of the metallic glass by micro alloying. Adding Iron or Cobalt to the PdNiP BMG leads to a huge change in ductility. While analyzing the dependence of the ductility of the present glasses on relaxation treatments, we utilize the fictive temperature concept to investigate the impact of minor alloying on the relative amount of free volume. Also the critical fictive temperature was measured to characterize the ductility of the new BMGs [1].

[1] G. Kumar, P. Neibecker, Y. H. Liu and J. Schroers, Nature communications 4, 1536 (2013).