Effect of residual stress on the indentation-induced interface delamination mechanism for a hard thin films on an ductile substrates

Hard thin films are often subjected to high loadings in the engineering applications. The shear and normal delaminations formed in the system including hard thin films and ductile substrates under the contact loading affect the reliability of the materials. The great residual stress in the hard thin films influences the interface between the films and the substrates, even resulting in the failure of the interface. In this paper, the effect of residual stress on the interface delamination of the hard thin films on ductile substrates is simulated by the cohesive model and finite element method. The critical indentation depth and critical load are obtained under alterable residual stress when the shear or normal delamination occurs, indicating the delamination mechanism induced by indentation. The failure mechanism map for the interface between the hard thin films and the ductile substrates is indicated when the residual stress is considered. This provides guidelines for engineering applications of thin films and the measurement of bonding behavior at the interface by using indentation.