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Atomic simulations of kinetic friction and its velocity dependence at Al/Al and alpha-Al2O3/alpha-Al2O3 interfaces

Zhang, Qing and Qi, Yue and Hector, Louis G., Jr. and Çağin, Tahir and Goddard, William A., III (2005) Atomic simulations of kinetic friction and its velocity dependence at Al/Al and alpha-Al2O3/alpha-Al2O3 interfaces. Physical Review B, 72 (4). Art. no. 045406. ISSN 1098-1021. http://resolver.caltech.edu/CaltechAUTHORS:ZHAprb05

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Abstract

Kinetic friction during dry sliding along atomistic-scale Al(001)/Al(001) and alpha-Al2O3(0001)/alpha-Al2O3(0001) interfaces has been investigated using molecular dynamics (MD) with recently developed Reactive Force Fields (ReaxFF). It is of interest to determine if kinetic friction variations predicted with MD follow the macroscopic-scale friction laws known as Coulomb's law (for dry sliding) and Stokes' friction law (for lubricated sliding) over a wide range of sliding velocities. The effects of interfacial commensuration and roughness on kinetic friction have been studied. It is found that kinetic friction during sliding at commensurate alpha-Al2O3(0001)/alpha-Al2O3(0001) interfaces exceeds that due to sliding at an incommensurate alpha-Al2O3(0001)/alpha-Al2O3(0001) interface. For both interfaces, kinetic friction at lower sliding velocities deviates minimally from Coulombic friction, whereas at higher sliding velocities, kinetic friction follows a viscous behavior with sliding damped by thermal phonons. For atomically smooth Al(001)/Al(001), only viscous friction is observed. Surface roughness tends to increase kinetic friction, and adhesive transfer causes kinetic friction to increase more rapidly at higher sliding velocities.


Item Type:Article
Additional Information:©2005 The American Physical Society (Received 15 September 2004; revised 1 February 2005; published 5 July 2005) The authors wish to acknowledge Dr. Y.T. Cheng for several stimulating discussions on aluminum engine friction and for his careful review of earlier versions of the manuscript, and Dr. M. H. Müser for useful discussions on the results. Support of the Caltech research was provided through a grant from General Motors. The facilities of MSC are supported by funding from ONR-DURIP, ARO-DURIP, and Beckman Institute with additional funding from NSF, NIH, DoE, ONR, DARPA, ChevronTexaco, Seiko-Epson, Aventis Pharma, and Berlex Biopharma. W.A.G. and T.C. wish to thank their friend and colleague the late Dr. Mike Gardos (Hughes Aircraft Co and Raytheon) whose aggressive pursuit of the fundamentals in tribology has stimulated us and many others to help transform tribology into a science.
Subject Keywords:aluminium; aluminium compounds; sliding friction; molecular dynamics method; interface roughness; surface roughness; plastic flow
Record Number:CaltechAUTHORS:ZHAprb05
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:ZHAprb05
Alternative URL:http://dx.doi.org/10.1103/PhysRevB.72.045406
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:1845
Collection:CaltechAUTHORS
Deposited By: Archive Administrator
Deposited On:20 Feb 2006
Last Modified:26 Dec 2012 08:46

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