Structural state and physical-mechanical properties of multilayer vacuum arc Ti/TiN coating

Abstract. Problem. Increasing the resource of the cutting tools in conditions of variable load is of great importance, as it affects not only the cost of production but also the competitiveness of the enterprise. A wide range of properties of vacuum arc multilayer coatings allows them to be used in mechanical engineering to increase the performance of the tools in the variable conditions of cutting. Goal. The goal is to study the structural state and physical and mechanical properties of vacuum arc multilayer Ti/TiN coatings. To achieve the goal, it is necessary to analyze the effect of the thickness of the titanium layer and the amount of negative stress on the substrate on the structure, stress-strain state, and physical and mechanical properties of the multilayer Ti/TiN coating with relatively thick layers of titanium nitride. Methodology. Multilayer Ti/TiN coatings were obtained in the Bulat-6 vacuum-arc installation. The study of mechanical characteristics was carried out by the indentation method using the MicronGama microindenter. Structural studies of the samples were carried out on a DRON-3M diffractometer. Electron microscopic studies were performed on a JEOL JSM-840 scanning electron microscope. Originality. It was found that in titanium nitride layers with a thickness of 300 nm or more, a texture develops when a voltage is applied to the substrate. The degree of texture perfection increases with increasing layer thickness. When the thickness of the titanium layer is from 30 nm to 250 nm, the development of the stress-strain state in the titanium nitride layers takes place without significant relaxation. The mechanical properties of the Ti/TiN multilayer coating remain quite high (hardness 33.7...36.3 GPa with a modulus of elasticity 413...434 GPa) when the thickness of the titanium layer is less than 125 nm. Practical value. Increasing the crack resistance of Ti/TiN multilayer coatings due to the introduction of titanium layers makes their use promising for hard loads.