Berlin 2018 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 44: Topical Session (Symposium EPS and MM): Mechanical Properties at Small Scales

MM 44.3: Vortrag

Mittwoch, 14. März 2018, 17:45–18:00, H 0107

Interface mediated creep behavior of Cu-Zr metallic glass composites — •Constanze Kalcher, Tobias Brink, and Karsten Albe — Technische Universität Darmstadt, Fachbereich Material- und Geowissenschaften, Fachgebiet Materialmodellierung, Otto-Berndt-Str. 3, D-64287 Darmstadt, Germany

Metallic glasses are known for their high yield strength and resilience, but their most severe shortcoming remains the brittle failure mechanism due to strain localization. A more homogeneous deformation behavior at room temperature can be enforced by including crystalline secondary phases. Their role in the deformation behavior under creep conditions, however, has not been fully assessed. In this molecular dynamics study, we show that the properties of the glass-crystal interfaces in such composites directly influence the creep behavior. To that end we model a Cu₆₄Zr₃₆ metallic glass with different phase fractions of the reinforcing Cu₂Zr Laves phase and manipulate the glass-crystal interfaces by disturbing the atomic structure in the immediate neighborhood of the crystallites. The different samples are then probed under the same creep conditions. In analogy to Borisov’s model for grain boundary diffusion, we observe that the creep rates of the metallic glass composites scale exponentially with the excess energy of the disturbed interfaces.