[SY-E13] Symposium E-13

[SY-E13] Vortex instabilities in the deformation of Cu|Au nanolaminates

Adrien Gola^1,2, Peter Gumbsch^2,3, ^○Lars Pastewka^1,3,2 (1.University of Freiburg, Germany, 2.Karlsruhe Institute of Technology, Germany, 3.Fraunhofer IWM, Germany)

Vortex-instabilities are typically associated with fluid-type flow patterns, such as the well-known Kelvin-Helmholtz instability that can be directly observed in cloud patterns. Recently, Vortex-type instabilities have been observed during the deformation of multilayered materials, both with nano- [1] and micrometer-sized [2] layers. We here use molecular dynamics simulation to investigate Vortex formation in Cu|Au nanolaminates. Our simulations reveal an instability that leads to corotation of neighboring regions of the nanolaminate, giving rise to deformation pattern reminiscent of Kelvin-Helmholtz instabilities. Contrary to the latter instabilities, the plastic Vortex formation occurs at strains below 2 which appears compatible with strains experienced during frictional loading [1]. We compare our molecular dynamics results with deformation patterns generated through ideal plastic and fluid mechanical models.

[1] Luo, Z.-P., Zhang, G.-P. & Schwaiger, R. Microstructural vortex formation during cyclic sliding of Cu/Au multilayers. Scr. Mater. 107, 67-70 (2015).
[2] Pouryazdan, M., Kaus, B. J. P., Rack, A., Ershov, A. & Hahn, H. Mixing instabilities during shearing of metals. Nat. Commun. 8, 1611 (2017).