A Model of Pore Dissolution at Grain Boundaries during Annealing of an Ultra-Fine-Grained Aluminum Alloy

A theoretical model is proposed that describes the mechanism of dissolution of pores at grain boundaries in ultra-fine-grained materials during long-term annealing. Within the framework of the model, the dissolution of a pore occurs due to the emission of vacancies and the climb of grain-boundary dislocations along the grain boundary to the pore. It is shown that in this case a significant decrease in the total energy of the system occurs. The results of the model are in good agreement with the available experimental observations of pore dissolution during annealing of an ultra-fine-grained Al–Zr alloy.