Fatigue resistance of CrN thin films deposited by arc evaporation process on H11 tool steel and 2205 duplex stainless steel

Notwithstanding the wide use of PVD coated components, not only in fields where tribological behaviour is important and well assessed, fatigue behaviour is still object of research in applications where enhanced fatigue resistance is required. Aim of this paper is to analyse fatigue crack growth mechanisms and to relate nucleation site to microstructure and residual stress data. Two structural steels were used as substrate (H11 tool steel grade and 2205 duplex stainless steel grade), while a monolayer of CrN 5 mm depth was deposed as coating. Four points bending fatigue tests were carried out in order to obtain the bending fatigue limit. Experimental results obtained by Scanning Electron Microscopy analyses, residual stresses measurements and hardness evaluations carried out using a nanoindenter device were considered to explain the fatigue mechanisms involving a PVD coated part in terms both of nucleation site and crack growth process