One of the most fundamental questions in tribology concerns the area dependence of friction at the nanoscale. Here, experiments are presented where the frictional resistance of nanoparticles is measured by pushing them with the tip of an atomic force microscope. We find two coexisting frictional states: While some particles show finite friction increasing linearly with the interface areas of up...

Tribological conditions can change drastically during heavy loaded regimes as experienced in metal forming; this is especially critical when lubrication can only be applied at the early stage of the process because the homogeneous lubricant layer can break along the die-workpiece interface. In these cases, adopting a constant friction factor for the lubricant-surface pair may not be a valid ass...

Wearless friction is investigated in a simple mechanical model called Frenkel-Kontorova-Tomlinson model. We have introduced this model in [Phys. Rev. B, 53, 7539 (1996)] where the static friction has already been considered. Here the model is treated for constant sliding speed. The motion of the internal degrees of freedom is regular for small sliding velocities or weak interaction between the ...

This paper presents the finite element analysis to study the stress distribution of nickel based superalloy HASTELLOY C-2000 in end milling operation. A commercial finite element software was used to develop modeling and analysis the distribution of stress components in the machined surface after end milling of HASTELLOY C-22HS using coated carbide tools. The friction interaction along the tool...

Dynamic evolution of surface roughness and influence of initial roughness (S(a) = 0.282-6.73 µm) during friction and wear processes has been analyzed experimentally. The mirror polished and rough surfaces (28 samples in total) have been prepared by surface polishing on Ti-6Al-4V and AISI 1045 samples. Friction and wear have been tested in classical sphere/plane configuration using linear recipr...

We report on memory effects involved in the unsteady-state frictional response of a contact interface between silicone rubber and spherical glass probe when it is perturbed by changes orientation driving motion or velocity steps. From measurements displacement fields at interface, we show that observed can be accounted for non-uniform distribution sliding within interface. As consequence these ...

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We have investigated the changes in interfacial friction of toluene on mica and Ag(111) both in the presence and in the absence of interfacial C60 layers employing atomic force microscope (AFM) and quartz crystal microbalance (QCM) techniques. The lateral force measurements fail to detect C60 at the toluene/mica interface, presumably because the C60 is dislodged by the slowmoving probe tip. In ...

Owing to its superior mechanical properties, nanodiamond (ND) holds great potential to improve tribological characteristics of composites. In this study, we report on the wear and dry friction of epoxy-ND composites prepared from as-received and aminated ND across the length scale range from macro to nano. Comparison of macroscale, microscale, and nanoscale frictional behavior shows that ND is ...

The failure reasons of reciprocating sealing in OPI-1800AWS fracturing pump are analyzed by scanning electron microscope technology (SEMT). The lubrication mechanism of plunger seal friction pair is analyzed by hydrodynamic lubrication theory. During its discharge and suction stroke, the reciprocating sealing friction pair meets the conditions of hydrodynamic lubrication, a certain thickness of...