Print Email Facebook Twitter Friction of atomically stepped surfaces Title Friction of atomically stepped surfaces Author Dikken, R.J. (TU Delft (OLD) MSE-7) Thijsse, B.J. (TU Delft (OLD) MSE-7) Nicola, L. (TU Delft (OLD) MSE-7) Date 2017 Abstract The friction behavior of atomically stepped metal surfaces under contact loading is studied using molecular dynamics simulations. While real rough metal surfaces involve roughness at multiple length scales, the focus of this paper is on understanding friction of the smallest scale of roughness: atomic steps. To this end, periodic stepped Al surfaces with different step geometry are brought into contact and sheared at room temperature. Contact stress that continuously tries to build up during loading, is released with fluctuating stress drops during sliding, according to the typical stick-slip behavior. Stress release occurs not only through local slip, but also by means of step motion. The steps move along the contact, concurrently resulting in normal migration of the contact. The direction of migration depends on the sign of the step, i.e., its orientation with respect to the shearing direction. If the steps are of equal sign, there is a net migration of the entire contact accompanied by significant vacancy generation at room temperature. The stick-slip behavior of the stepped contacts is found to have all the characteristic of a self-organized critical state, with statistics dictated by step density. For the studied step geometries, frictional sliding is found to involve significant atomic rearrangement through which the contact roughness is drastically changed. This leads for certain step configurations to a marked transition from jerky sliding motion to smooth sliding, making the final friction stress approximately similar to that of a flat contact. To reference this document use: http://resolver.tudelft.nl/uuid:a0b9854d-0841-4fb7-b549-04124c50d26a DOI https://doi.org/10.1103/PhysRevB.95.104106 ISSN 1098-0121 Source Physical Review B (Condensed Matter and Materials Physics), 95 (10), 1-10 Part of collection Institutional Repository Document type journal article Rights © 2017 R.J. Dikken, B.J. Thijsse, L. Nicola Files PDF PhysRevB.95.104106.pdf 2.18 MB Close viewer /islandora/object/uuid:a0b9854d-0841-4fb7-b549-04124c50d26a/datastream/OBJ/view