Dresden 2020 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 51: Computational Materials Modelling - Mechanical Properties
MM 51.5: Talk
Thursday, March 19, 2020, 11:15–11:30, IFW B
The emergence of small-scale self-affine surface roughness from deformation — •Wolfram Nöhring1, Adam Hinkle1,2, Richard Leute1, Till Junge6, and Lars Pastewka1,3,4,5 — 1Department of Microsystems Engineering, University of Freiburg, Germany — 2Materials, Physical and Chemical Sciences Center, Sandia National Laboratories, USA — 3Institute for Applied Materials, Karlsruhe Institute of Technology, Germany — 4Freiburg Materials Research Center, University of Freiburg, Germany — 5Cluster of Excellence livMatS, University of Freiburg, Germany — 6Department of Mechanical Engineering, École Polytechnique Fédérale de Lausanne, Switzerland
Surfaces in nature and engineering are often rough across many length scales, with self-affine scaling of heights. There is presently no unifying theory for the origin of roughness and self-affinity. One likely contributor is plastic deformation. In this work, the link between plastic deformation and self-affine roughness is investigated using molecular dynamics simulations. Three different materials are considered, single-crystal Au, the High Entropy Alloy Ni36.67Co30Fe16.67Ti16.67, and amorphous Cu50Zr50. Bi-axial compression of initially atomically flat surfaces of these materials is simulated. A self-affine topography emerges in all cases during plastic deformation, despite differences in composition, structure, and deformation mechanisms. Moreover, it is shown that non-affine displacements in the bulk scale self-affinely as well. The results indicate that self-affinity of plastic deformation is sufficient to explain the emergence of self-affine surface roughness.