Deformation behavior and wear resistance of hard TiCN and TiCN/Ti coatings on Ti6Al4V alloy
Monolayer titanium carbide nitride (TiCN) and multilayer TiCN reinforced titanium (Ti) are coated on the surface of Ti6Al4V alloy by Filtered Arc Deposition System (FADS). Surface chemical composition has been characterized by an X-ray diffraction (XRD). Wear resistance of TiCN coating and TiCN/Ti coating have been detected by hommel tester T1000. Hardness and deformation mechanisms of the multilayer coatings are investigated using depth-sensing indentation comparison with the monolayer TiCN coatings. Focused Ion Beam (FIB) and Transmission Electron Microscopy (TEM) are used to identify the fracture modes of the coatings. The TEM image observations show that the inclined crack is the dominant crack in the monolayer TiCN coating while small bending crack is the dominant crack in the multilayer TiCN/Ti coating. The Ti layer with good ductility could efficiently suppress the crack propagation and absorb more indent energy.