Time: 3:00 p.m.
Place: Fraunhofer IWS Seminar, Dresden, Germany
Modern structural materials are seldom single crystals, but exhibit a polycrystalline, multiphase, often hierarchical microstructure. Consequently, ”there is not one material property that is unaffected by the presence or absence of grain boundaries.” (A.D. Smith 1996), and the effect of interfaces on the mechanical properties of materials is in fact manyfold. Nowadays tailored microstructures, containing certain arrangements of grain boundaries with specific properties that can even be tuned by segregation engineering, are within experimental reach. This gives additional impetus to the developement of predictive material models that bridge between the atomistic details of grain boundaries and the effective properties of the microstructure, and can help to identify microstructures with optimised mechanical properties. Numerical simulation methods, that either allow the study of relevant processes on their characteristic length scale, or can be used to pass on information from finer to coarser length scales, are common tools in this respect. In the presentation some examples of atomistic studies of grain boundaries will be given that illustrate current developments and the challenges that one has to face when trying to extract effective mechanical behaviour and to link it to fundamental physical and geometrical properties of the interfaces.