Structure and mechanical properties of PVD coatings deposited onto the X40CrMoV5-1 hot work tool steel substrate

This work presents the research results on the structure and mechanical properties of coatings deposited by PVD methods on the X40CrMoV5-1 hot work tool steel substrates. The tests were carried out on CrAlSiN, CrAlSiN+DLC, CrN and WC/a-C:H coatings. It was found that tested coatings have nanostructural character with fine crystallites, while their average size fitted within the range 3-13 nm, depending on the coating type. The coatings demonstrated a dense cross-sectional morphology as well as good adhesion to the substrate, the latter not only being the effect of interatomic and intermolecular interactions, but also by the transition zone between the coating and the substrate, developed as a result of diffusion that caused mixing of the elements in the interface zone and the compression stresses values. The critical load L_C2 lies within the range 45-55 N, depending on the coating type. The coatings demonstrate a high hardness (4000 HV).