Crystalline misfit-angle implications for solid sliding

TL;DR

This paper models how the misfit angle between crystalline surfaces affects static friction and sliding behavior, providing insights into the statistical distribution of energy barriers and the transition from stick-slip to smooth sliding.

Contribution

It introduces a simple model linking misfit angles and contact area to the distribution of energy barriers, predicting macroscopic sliding behavior from microscopic properties.

Findings

Low temperature favors stick-slip motion.

High temperature promotes smooth sliding.

Statistical properties of energy barriers are crucial for understanding friction.

Abstract

For the contact of two finite portions of interacting rigid crystalline surfaces, we compute the dependence of the pinning energy barrier on the misfit angle and contact area. The resulting data are used to investigate the distribution of static frictional thresholds for a contact of polycrystal surfaces, as occurs at the touching points of dry or even lubricated friction. The simplicity of the model allows us to investigate a broad contact-size and angular range, thus obtaining the statistical properties of the energy barriers opposing sliding for a single asperity. These statistical properties are used as the input of a master-equation model to predict the sliding properties of two macroscopic surfaces in contact. The model is consistent with the well-established result that low temperature should generally favor stick-slip motion, while at high temperature sliding should be smooth.