title: Effect of stress nonhomogeneity on the shear melting of a thin boundary lubrication layer.
abstract: We consider the dynamical properties of boundary lubrication in contact between two atomically smooth solid surfaces separated by an ultrathin layer of lubricant. In contrast to previous works on this topic, we explicitly consider the heterogeneity of tangential stresses, which arises in a contact of elastic bodies that are moved tangentially relative to each other. To describe phase transitions between structural states of the lubricant we use an approach based on the field theory of phase transitions. It is assumed that the lubricant layer, when stressed, can undergo a shear-melting transition of first or second order. While solutions for the homogeneous system can be easily obtained analytically, the kinetics of the phase transitions in the spatially heterogeneous system can only be studied numerically. In our numerical experiments melting of the lubricant layer starts from the outer boundary of contact and propagates to its center. The melting wave is followed by a wave of solidification. This process repeats itself periodically, following the stick-slip pattern that is characteristic of such systems. Depending on the thermodynamic and kinetic parameters of the model, different modes of sliding with almost complete or only partial intermediate solidification are possible.
authors.affiliation: Berlin University of Technology, 10623 Berlin, Germany.|Sumy State University, 40007 Sumy, Ukraine.
authors.forename: Iakov A
authors.initials: IA
authors.lastname: Lyashenko
authors.affiliation: Berlin University of Technology, 10623 Berlin, Germany.|Donetsk Institute for Physics and Engineering, 83114 Donetsk, Ukraine.
authors.forename: Alexander E
authors.initials: AE
authors.lastname: Filippov
authors.affiliation: Berlin University of Technology, 10623 Berlin, Germany.|National Research Tomsk Polytechnic University, 634050 Tomsk, Russia.|National Research Tomsk State University, 634050 Tomsk, Russia.
authors.forename: Mikhail
authors.initials: M
authors.lastname: Popov
authors.affiliation: Berlin University of Technology, 10623 Berlin, Germany.|National Research Tomsk Polytechnic University, 634050 Tomsk, Russia.|National Research Tomsk State University, 634050 Tomsk, Russia.
authors.forename: Valentin L
authors.initials: VL
authors.lastname: Popov