Mechanical Properties and Residual Stress Measurement of TiN/Ti Duplex Coating Using HiPIMS TiN on Cold Spray Ti

Abstract

This study investigated the mechanical properties and the residual stress of high-power impulse magnetron sputtering (HiPIMS) titanium nitride (TiN) thin film capping on cold spray titanium (Ti) coating. This TiN/Ti duplex coating was deposited on the Ti substrate, and the cold spray titanium (Ti) coating was prepared in three cases with different numbers of layers. The study determined Young’s modulus, hardness, and roughness of TiN thin film and cold spray Ti coatings by nano-indentation and AFM. The residual stress measurement of TiN/Ti duplex coating was conducted using the ring-core drilling method. A focused ion beam (FIB) drilled the TiN/Ti duplex coating with various milling depth steps. The corresponding images were obtained with a scanning electron microscope (SEM). The relationship between surface deformations and relaxation stress after each milling depth step was obtained using the digital image correlation (DIC) method. The results showed TiN/Ti duplex coating exhibited excellent mechanical properties, and the residual stresses were not significantly changing with different Ti cold spray substrates, showing the feasibility of coating technology for the future applications in the aerospace industry.