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MM: Fachverband Metall- und Materialphysik
MM 9: Liquid and Amorphous Metals - Brittle-to-ductile Transition
MM 9.4: Vortrag
Montag, 16. März 2020, 12:30–12:45, IFW D
Cooling rate, temperature and applied strain rate effects on the brittle-to-ductile transition in metallic glasses — •Xudong Yuan1, Daniel Şopu1,3, and Jürgen Eckert1,2 — 1Erich Schmid Institute of Materials Science, Leoben, Austria — 2Montanuniversität Leoben, Leoben, Austria — 3Technische Universität Darmstadt, Darmstadt, Germany
The effects of cooling rate, temperature and applied strain rate on the tensile deformation behavior of Cu64Zr36 metallic glass (MG) are investigated using large-scale molecular dynamics simulations. An increase in quenching rate during sample preparation, as well as an increase of temperature or applied strain rate, affects the shear band nucleation and propagation processes and causes a brittle-to-ductile transition. High quenching rates lead to a low density of closed packed Cu-centered full icosahedra and by sampling of the saddle points on the potential energy surface we found lower barrier energy for local atomic rearrangement as compared to those MGs obtained at low quenching rates. High temperatures will increase the kinetic energy of the atoms, which leaves the atoms to easily rearrange and increases the probability of thermal activation of shear transformation zones. Finally, during deformation at high strain rates, the stored elastic energy has not enough time to redistribute through local elastic distortions along the maximum shear stress direction and, consequentially, the MGs deform homogeneously.