Flow Stress And Dislocation-interfaceInteraction In Thin Metallic Films: An AtomisticAnalysis

Abstract

The atomistics of interface-mediated plasticity in thin metallic films is numerically studied. Molecular statics simulations were undertaken to model the tensile response of the free-standing and substrate-attached films. In the freestanding film dislocation glide readily occurs, inducing slip steps at both surfaces of the film. The existence of an interface with the substrate constrains the dislocation motion and restricts the slip steps to only the free surface. The propensities of film plasticity and of spreading of relatively energetic atoms associated with the dislocation near the interface are both dictated by the capability of atoms to slide along the interface. The flow stress of the film can be correlated with the dislocation activities. The evolution of voiding damage leading to final fracture of the film is also simulated.