Analysis on the cracking of thin hard films considering the effects of interfacial delamination

Cracking of thin hard films on ductile substrates under indentation was investigated considering the effects of interfacial delamination. The fracture behavior of the film was analyzed using the extended finite element method (XFEM), and the evolution of the interfacial delamination was simulated using a cohesive zone model (CZM). Results showed that at the location within the contact area, interfacial delamination hastened the cracking at the bottom surface of the film because of the enhancement of the film stretching. However, at the location outside the contact area, the cracking on the top surface of the film was postponed by the interfacial delamination due to the reduction in the film bending. The interfacial strength and toughness had significant effects on the delamination evolution at film/substrate interfaces, and therefore strongly affected the cracking behavior of thin hard films.