Interdependence between stress and texture in arc evaporated Ti–Al–N thin films

Ex-situ X-ray diffraction was used to characterize the stress state and texture of TiAlN monolayer and TiN/TiAlN multilayer hard coatings deposited on WC–Co and tool steel substrates using the cathode arc evaporation method. For all coatings the compressive residual stress was found to be higher in the film deposited on tool steel than that deposited on WC–Co; this is due to the difference in the linear thermal expansion coefficient of the two substrates. X-ray diffraction polar scan measurements showed that the preferred orientation of the crystallites exhibits cylindrical symmetry but it is inclined with respect to the sample surface. Moreover, the inclination angle of the (002) diffracting planes increases with the increase of the residual stress in the coating. Different mechanisms that could explain the interdependence between fiber texture and residual stress are discussed.