Regensburg 2016 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 6: Liquid and Amorphous Metals II: Shear bands

MM 6.5: Vortrag

Montag, 7. März 2016, 12:30–12:45, H52

A Molecular Dynamics Simulation Study On The Avalanche Dynamics And The Microstructure Evolution Of The Glassy Cu50Zr50 System. — •Alexandra Lagogianni and Konrad Samwer — Erstes Physikalisches Institut, Goettingen, Deutschland

The presence of avalanches/stress drops in the plastic regime of BMGs upon mechanical deformation, and their direct correlation with the formation and arrest of single shear bands [1-2], has been revealed by several experimental studies the last decades. Aiming to gain a deeper insight of this phenomenon on a smaller length scale we employed molecular dynamics simulations of an amorphous CuZr system under tension. Different strain rates were tested at room and glass transition temperature and the distribution of stress drops sizes was found to follow a power law which exponent is in agreement with that predicted by the avalanche dynamics theory [3]. It came out that the serrated flow takes place even from the very beginning of the elastic region while the possible alterations that occur in the microstructure of the system were exhaustively studied. The present simulation results provide a theoretical confirmation of the experimental findings and a deeper and qualitative understanding of the origin of avalanches in a metallic glass.

[1] Krisponeit, J.O, Pitikaris S., Avila K.E., Küchemann, S., Krüger, Samwer ,K. Nature Communications 5, 3616 (2014). [2] Dalla Torre, F.H., Dubach, A., Nelson A., Löffler J.F. Materials Transactions 48, 7, pp. 1774-1780 (2013). [3] Dahmen K.A, Ben-Zion Y., Uhl J.T. Nature Physics 7 pp. 554-557 (2011).