Plastic deformation of freestanding thin films: Experiments and modeling

摘要: Experimental measurements and computational results for the evolution of plastic deformation in freestanding thin films are compared. In experiments, stress–strain response two sets Cu is determined plane-strain bulge test. One set samples consists electroplated films, while other sputter-deposited. Unpassivated passivated on one side both sides considered. The calculations carried out within a two-dimensional plane strain framework with dislocations modeled as line singularities an isotropic elastic solid. film by unit cell consisting eight grains, each which has three slip systems. initially free then nucleate from specified distribution Frank–Read sources. grain boundaries any film-passivation layer interfaces taken to be impenetrable dislocations. Both experiments computations show: (i) flow strength that greater than unpassivated (ii) hysteresis Bauschinger effect increases increasing pre-strain small or absent. Furthermore, experimental 0.2% offset yield stress, good quantitative agreement.