Stick-slip and temperature effect in the scratching of materials

The stick-slip process and temperature effect in scratch testing of materials have been studied. For a poly(methyl methacrylate) (PMMA) polymer scratched by a conical diamond indenter, both the amplitude and period of the stick-slip at room temperature increase with the normal load and decrease with the driving speed. An increase in temperature leads to an increase in stick-slip amplitude and period, as well as in the average horizontal force. For bismuth metal scratched by a conical tungsten indenter, the surface temperature in the contact area reveals fluctuations related to the stick-slip motion.