Dynamics of the contact between a ruthenium surface with a single nanoasperity and a flat ruthenium surface: Molecular dynamics simulations
- Departamento de Fisica, Universidade Federal de Ouro Preto, Ouro Preto, MG 35400-000 (Brazil)
- Department of Physics, Yeshiva University, 500 West 185th Street, New York, New York 10033 (United States)
We study the dynamics of the contact between a pair of surfaces (with properties designed to mimic ruthenium) via molecular dynamics simulations. In particular, we study the contact between a ruthenium surface with a single nanoasperity and a flat ruthenium surface. The results of such simulations suggest that contact behavior is highly variable. The goal of this study is to investigate the source and degree of this variability. We find that during compression, the behavior of the contact force displacement curves is reproducible, while during contact separation, the behavior is highly variable. Examination of the contact surfaces suggests that two separation mechanisms are in operation and give rise to this variability. One mechanism corresponds to the formation of a bridge between the two surfaces that plastically stretches as the surfaces are drawn apart and eventually separate in shear. This leads to a morphology after separation in which there are opposing asperities on the two surfaces. This plastic separation/bridge formation mechanism leads to a large work of separation. The other mechanism is a more brittle-like mode in which a crack propagates across the base of the asperity (slightly below the asperity/substrate junction) leading to most of the asperity on one surface or the other after separation and a slight depression facing this asperity on the opposing surface. This failure mode corresponds to a smaller work of separation. This failure mode corresponds to a smaller work of separation. Furthermore, contacts made from materials that exhibit predominantly brittle-like behavior will tend to require lower work of separation than those made from ductile-like contact materials.
- OSTI ID:
- 21538268
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 83, Issue 13; Other Information: DOI: 10.1103/PhysRevB.83.134101; (c) 2011 American Institute of Physics; ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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