Nanoindentation of hard multilayer coatings: Finite element modelling

Stress concentrations undermine the load-bearing ability of superhard TiSiN coatings. Experimental studies have shown that multilayer coatings that contain TiSiN layers alternating with ceramic layers with dissimilar mechanical properties suppress contact damage during nanoindentation. In this work, nanoindentation-induced deformation in TiSiN-based multilayer coatings was simulated by means of finite element modelling (FEM). Stress distributions under moderate indentation loading in the structure were quantified with particular emphasis on the relationship between stress concentrations and crack initiation. The results showed that the structural layering can be used to modify the stress distribution, and lower the overall stress level within the coating. In the case of radial tensile stresses at the coating/substrate interface, a reduction ∼50% has been achieved through layering. The resistance to shear damage can also be improved by optimising the multilayer structure.