Direct quantification of mechanical responses of TiSiN/Ag multilayer coatings through uniaxial compression of micropillars

The TiSiN/Ag multilayer coatings with fixed TiSiN layer thickness and different individual Ag layer thicknesses were prepared by arc ion plating. Quantification of mechanical response of TiSiN/Ag multilayer coatings through uniaxial micropillar compression tests was carried out to identify the elastic modulus, fracture strength, deformation and failure mechanism. The deformation and failure behavior of the micropillars assessed by direct scanning electron microscopy observation after the uniaxial compression tests revealed a linear increase of stress with strain up to a fracture point for all 1-μm micropillars, indicating an elastic response with brittle failure. In addition, in-situ micro-compression was carried out mainly on the micropillars with diameters of 600 nm and 300 nm; the stress-strain curves show an initial linear elastic response until the yield point was reached, followed by plastic deformation with a total strain of 27.99% and 42.7%, respectively. Moreover, size effect was also found in the micropillar compressions in which, the 300-nm micropillar showed the highest fracture strength of 16.71 ± 0.63 GPa.