Abstract
The molecular dynamics computer simulation method is used to study the indentation and scraping of a clean metal surface by a hard diamond tool. Both two and three dimensional models are considered. The embedded atom method is used to represent a metallic work material. To make connection with macroscopic continuum models, we calculate the stress field from the atomistic computer experiment. The agreement is excellent during the initial elastic indentation. However, the onset of plastic deformation occurs at a much higher yield stress in the atomistic simulations. This enhanced hardness, with shallow indentations, corresponds to the theoretical yield stress required to create dislocations and leads to a dramatic increase in specific cutting energy for small depths of cut. Remarkably, the range of plastic deformation in our three dimensional simulations is only a few lattice spacings, unlike the several hundred lattice spacings dislocations readily propagate in our two dimensional simulations. This suggests that dislocations are not a very efficient mechanism for accommodating strain at this nanometer length scale in three dimensions.
Work performed under the auspices of the U.S. Department of Energy by the Lawrence Livermore National Laboratory under contract No. W-7405-ENG-48.
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Belak, J., Stowers, I.F. (1992). The Indentation and Scraping of a Metal Surface: A Molecular Dynamics Study. In: Singer, I.L., Pollock, H.M. (eds) Fundamentals of Friction: Macroscopic and Microscopic Processes. NATO ASI Series, vol 220. Springer, Dordrecht. https://doi.org/10.1007/978-94-011-2811-7_25
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DOI: https://doi.org/10.1007/978-94-011-2811-7_25
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