This work analyses the effect of annealing conditions on tribolayer formation in copper under dry sliding conditions. Cold rolled material and samples annealed during 15, 30 and 45 min at 600 °C show an increase in grain size, decrease in hardness and increase in toughness and ductility with time. Electron backscattered diffraction maps describe the severe plastic deformation of a nanostructured tribolayer. Friction coefficients decrease with annealing times, while surface damage diminishes. Wear is lower in the softer material. This is explained by the energy required to produce surface damage, in combination with the energy transmitted to the substrate by friction.

This work studies the ultrafine subsurface layer produced in Al-Sn and Cu alloys in contact with AISI9840 steel. The tribological tests were conducted at room temperature without lubrication in a coaxial tribometer. A first microstructural characterization was performed using conventional scanning electron microscopy (SEM) and atomic force microscopy (AFM). Grain refinement mapping was performed by means of Electron Backscattering Diffraction (EBSD). The wear process, during which tribolayers are formed, leads to significant differences between the structure of the sub-micrometrical layer below the tribolayer and that of the bulk. SEM images show severe mechanical mixing in the surface of the worn zones, whereas EBSD observations allow identifying the mechanically homogenized layers as a sub-micro-crystalline material with a cellular structure aligned along the sliding direction.