Interstitial impurities at grain boundaries in metals

The investigation of segregation and embrittlement at grain boundaries in metals is a research area with a long tradition. In recent times, the feasibility of computational studies on the atomic scale gave a new impetus to the community. In this feature article we summarize our contributions to the understanding of segregation of interstitial impurities and embrittlement at grain boundaries in the bcc transition metals against the background of research activities in the field. We mainly discuss the benefits and limitations of ab-initio electronic structure calculations.