Determination of elastoplastic properties of TiO2 thin films deposited on dual phase stainless steel using nanoindentation tests

In recent years, the extraction of mechanical behaviour of thin films by nanoindentation using sharp indenter geometry has been extensively studied. This work investigates the mechanical properties of TiO2 thin film (1 µm thickness) deposited by spin coating on dual phase Duplex stainless steel and glass substrates. Experiments are carried out with different sharp triangular pyramids (a Cube corner and a Berkovich indenter) using a commercial Nano Indenter® XP apparatus. The substrate effect has been counteracted and an inverse method proposed in literature for bulk material has been adapted to assess the elastoplastic parameters of the tested thin film directly from estimation of the hardness and elastic modulus values determined experimentally. This experimental method, coupled with two dimensional finite elements modelling, allows the determination of the mechanical behaviour of the film over the Duplex steel.