Grain size effect on interfacial segregation in nanomaterials
Résumé
Segregation of impurities to grain boundaries in materials impact their structural, mechanical, electrical or
functional properties. In the present paper, a theoretical study of the influence of grain size on grain boundaries
segregation in a binary system by coupling the McLean theory, the concept of excess number with the grain
boundaries fraction, is presented. The obtained results show that both grain boundary and bulk solute content
decrease with reducing the grain size. However, it is shown the equilibrium segregation rate to grain boundaries
increases. This effect is enhanced when the grain size is lower than 10 μm and thus should be amplified in
nanomaterials. This size dependence is larger at low temperatures, where segregation becomes more
pronounced.