It was recalled that grain boundaries were sources and sinks for bulk vacancies, but that the exchange that occurred between the grain boundary and the bulk, under stress, remained obscure. It was shown here that grain boundaries would act as sources and emit vacancies when a compressive stress was exerted upon them, and as sinks which absorbed vacancies when a tensile stress was exerted. At the same time, this process produced non-equilibrium grain-boundary solute segregation and dilution. A set of kinetic equations was established in order to describe this process. An attempt was made to simulate the experimental data, using kinetic equations, in order to justify the physical process.

Creating and Destroying Vacancies in Solids and Non-Equilibrium Grain-Boundary Segregation. X.Tingdong: Philosophical Magazine, 2003, 83[7], 889-99