During the project in particular the dependence of the SFE on the chemical composition was investigated. For example, we have indentified the influence of the chemical and magnetic ordering on the composition dependence of stacking fault energies in austenitic Fe1-xMnx alloys . Furthermore, the impact of Al and Si on the phase stability of the two involved crystal structures, fcc and hcp, was investigated . One of our main findings, however, is the delicate dependence of the SFE on the interstitial carbon content and the role of an anti-Suzuki effect in this context. Our ab initio calculations reveal a strong increase of the SFE with C concentration, but simulateously a strong driving force for C to leave the defect region. By a careful evaluation under which circumstance the onset of nano-diffusion should take place, deviating trends on composition dependence of the SFE in experiment have been explained .