Stress and dislocations in thin metal layers

According to experimental findings there are types of loading for which it is more difficult to plastically deform small metal structures than the corresponding massive metal. This occurs when at least one of the dimensions of the structure is at the micrometer scale or smaller. It is for instance the case of thin metal coatings: the thinner is the film, the more difficult it is to deform it plastically. This feature is in contrast with what expected on the basis of classical plasticity theories, which predict a size-independent mechanical response. In this thesis the size effect in thin films is studied by means of two-dimensional discrete dislocation plasticity. Plasticity is treated as the collective motion of edge dislocations on prescribed slip systems. The framework contains an intrinsic length scale- the dislocation Burgers vector- which is a necessary condition to capture a size effect. ... Zie: Summar