Interface Separation in Residually-Stressed Thin-Film Structures

摘要

Plasticity is a significant contributor to the interfacial fracture resistance of multilayer thin-film structures containing ductile layers. Salient parameters affecting plasticity contributions to interfacial fracture energy including the ductile layer thickness, yield strength, and the maximum cohesive stress governing interface separation, have been reported. However, the effects of residual stresses in the thin-film layers on such plasticity contributions have not been considered. We explore the effect of residual stresses on debonding with particular attention to the relationship between the stress state in both ductile and elastic layers and the resulting macroscopic debond energy. Using multiscale simulations it is shown that residual thin-film stresses can alter plasticity in the ductile layer and significantly influence the macroscopic fracture energy. A simple yield-based model to account for this behavior is proposed.