Electronic origin of void formation in fcc metals

Voids can be formed by supersaturation of vacancies created by energetic particle irradiation, quenching, or mechanical deformation. By using multiscale simulations, we studied the thermodynamic processes of void formation in Al. We discovered an important connection between vacancy-induced bonding cage and the tendency of void formation in fcc metals. A model is proposed to explain the observed connection, linking the electronic structure to the free energy of a void nucleus. We found that the formation of the bonding cages is closely related to the directionality of the chemical bonding in fcc metals.