On the relation between the anisotropies of grain boundary segregation and grain boundary energy

Abstract

Abstract Recently developed models of grain boundary segregation and grain boundary energy, as a function of the 5 macroscopic parameters of grain boundary orientation, have been used to predict the behavior of a simple face centred cubic alloy. It is shown that the equilibrium composition, as well as the composition profile, on one side of a boundary with a given terminating plane, depends on the crystallographic orientation of the terminating plane of the other side of the grain boundary. These predictions are confirmed by recent measurements of Nb segregation to TiO2 grain boundaries. In addition, the models show stronger solute segregation to higher energy grain boundaries of the pure solvent. This result is also confirmed by the experimental distribution in orientation space of Nb segregation to TiO2 grain boundaries, when it is compared to the orientation distribution of the grain boundary energy of pure TiO2. The overall results are consistent with expectations from the Gibbs adsorption isotherm, and indicate that grain boundary energy anisotropy is decreased by grain boundary segregation.