Interfacial Segregation in Bicrystals: A Database for Grain Boundary Design of Polycrystals

Physical meaning of thermodynamic parameters of segregation obtained from measurements of chemical composition of grain boundaries in poly crystals and bi crystals, and calculated for individual grain boundary sites is discussed. It is shown that the mean values of these parameters determined from the measurements on polycrystals can in exceptional cases represent the behavior of general grain boundaries. On the other hand, measurements of grain boundary segregation at individual grain boundaries can provide the values of segregation enthalpies and entropies representing behavior of a specific single grain boundary site. The latter data are appropriate for the use in the grain boundary design concept.