Determining of Young’s modulus of multi-layered structure by SAWs method

The surface acoustic waves (SAWs) technique is becoming an attractive tool for accurately and nondestructively characterizing the mechanical property of thin film. The theoretical equations for describing SAWs propagating on the multi-layered structure are derived in this study. The dispersion features of SAWs propagating on the example TiO2/TiN duplex film coated on titanium alloy are investigated to instruct an accurate and facile fitting process for determining Young´s modulus of TiO2/TiN duplex film. The dependence of dispersion relation on the elastic modulus of TiO2 and TiN as well as frequency are provided and discussed in detail. The study shows an obvious influence of multi-layered structure on the dispersion relation of SAWs. Numerical result shows that the dispersion curve is well separated. It confirms that the SAWs technique has high resolution on determining Young´s modulus of multi- layered structure.