Complexity of plastic instability in amorphous solids: Insights from spatiotemporal evolution of vibrational modes
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THE EUROPEAN PHYSICAL JOURNAL E
Regular Article
Complexity of plastic instability in amorphous solids: Insights from spatiotemporal evolution of vibrational modes J. Yang1 , J. Duan1,2 , Y.J. Wang1,2 , and M.Q. Jiang1,2,a 1 2
State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China School of Engineering Science, University of Chinese Academy of Sciences, Beijing 101408, China Received 5 July 2020 / Received in final form 15 August 2020 / Accepted 19 August 2020 Published online: 11 September 2020 c EDP Sciences / Societ` a Italiana di Fisica / Springer-Verlag GmbH Germany, part of Springer Nature, 2020 Abstract. It has been accepted that low-frequency vibrational modes are causally correlated to fundamental plastic rearrangement events in amorphous solids, irrespective of the structural details. But the mode-event relationship is far from clear. In this work, we carry out case studies using atomistic simulations of a three-dimensional Cu50 Zr50 model glass under athermal, quasistatic shear. We focus on the first four plastic events, and carefully trace the spatiotemporal evolution of the associated low-frequency normal modes with applied shear strain. We reveal that these low-frequency modes get highly entangled with each other, from which the critical mode emerges spontaneously to predict a shear transformation event. But the detailed emergence picture is event by event and shear-protocol dependent, even for the first plastic event. This demonstrates that the instability of a plastic event is a result of extremely complex multiple-path choice or competition, and there is a strong, elastic interaction among neighboring instability events. At last, the generality of the present findings is shown to be applicable to covalent-bonded glasses.
1 Introduction How crystalline solids deform plastically is fundamentally clear, thanks to extensive studies of a finite number of crystal types [1–3]. Under external stimuli, plastic arrangements always initiate around lattice defects such as dislocations and grain boundaries. Amorphous solids, by contrast, can exhibit an infinite variety of configurations where lattice defects are entirely lost [4]. In this case, elementary plastic events become elusive, and identifying their structural fingerprints poses a formidable challenge. Over the past decades, numerous efforts [5–11] have been made to define various predictors for amorphous plasticity. Pure structural parameters have proven to be distantly related to plastic rearrangements. But physical quantities involving dynamic properties or high-order structural information offer enhanced predictability. Elasticity is a material property, intermediate between structure and plasticity, which can act as a middle way
Contribution to the Topical Issue “Disordered, NonEquilibrium Systems: From Supercooled Liquids to Amorphous Solids” edited by Marco Baity Jesi, Yuliang Jin, Elijah Flenner, Marisa A. Frechero, Gustavo A. Appignanesi. Supplementary material in the form of a
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