The effects of subsurface deformation on the sliding wear behaviour of a microtextured high-nitrogen steel surface

The main goal of the present investigation was to understand the acting wear mechanisms for a microtextured high-nitrogen stainless steel under self-mating sliding wear conditions. Therefore, the worn surface and subsurface was observed by means of scanning and transmission electron microscopy, respectively. It was shown that the alloying with nitrogen has a distinct effect on the dislocation movement under plastic deformation. No dislocation cells were found under the wear track which generally lead to the formation of large and flake-like debris. Moreover, the subsurface of high-nitrogen steels seems to be stabilized by strain- and transformation hardening thereby moving the point of failure into a nanocrystalline top surface layer. Consequently, all wear particles are in the submicron regime. A novel surface modification topography for stainless steels was developed which can trap and subsequently fix the nanosize wear debris in microsize pockets. As a result, the emission of particles into the surroundings of the system is reduced and a smooth hybrid surface is generated during the running-in which is expected to have superior tribological properties.