Place: Max-Planck Institut für Eisenforschung, Düsseldorf, Germany
The mechanical properties of metals and alloys are significantly influenced by the properties of interfaces in their microstructure. Incoherency stresses at grain boundaries and grain boundary sliding at elevated temperatures affect the strength and deformability of the material. Furthermore grain boundaries are acting as source, sink, or barrier for dislocations, and thus influence the hardening behaviour of metals. Grain boundaries, in turn, can be strengthened or embrittled by the presence of segregated impurities. At higher concentrations, impurities lead to precipitates and again new interfaces in the microstructure. In this talk I will introduce the efforts of the ICAMS group „mechanical properties of interfaces“ to gain insight into some of the topics described above. We employ mainly ab initio calculations and molecular dynamics simulations with embedded atom potentials to investigate the elastic and plastic properties of grain boundaries as a function of their geometric degrees of freedom, the segregation behaviour of interstitial impurities in bcc metals, and the influence of precipitates at grain boundaries on the mechanical properties of the material. The focus of the presentation will be on the effect of carbon in bcc iron and molybdenum.