Determining how the vacancies in excess of equilibrium concentration were created and destroyed in solids was crucial for understanding many of their physical characteristics and processes. Grain boundaries were known to be sources and sinks for bulk vacancies, but the exchange that might occur between the grain boundary and the bulk under a stress was still obscure. It was shown here that grain boundaries could work as sources to emit vacancies when a compressive stress was exerted on them, and as sinks to absorb vacancies when a tensile stress was imposed. At the same time, this physical process would produce solute non-equilibrium grain-boundary segregation and dilution. A set of kinetic equations was established in order to describe this physical process. An attempt was made to simulate the experimental data with the kinetic equations and thus 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