Characterization of TiN thin films subjected to nanoindentation using focused ion beam milling

Abstract The microstructure and surface morphology of a TiN hard, wear resistant coating on a V820 nitridable alloy ductile steel substrate following nanoindentation have been characterized using focused ion beam (FIB) milling. A TiN coating, ∼0.6 μm in thickness, was deposited on a ductile steel substrate using a cathodic arc evaporation (CAE) technique. Pop-in events were observed in the load–displacement curves and correlated to the observed microstructural features. Following nanoindentation with a 1 μm radius spherical indenter at loads of 100 mN and 500 mN, circumferential cracks were observed inside the indentation. Observations of nanoindented cross-sections prepared using FIB revealed both columnar cracks in the coating and shear steps at the coating–substrate interface. These structural features were observed at higher resolution using a transmission electron microscope (TEM).