Interplay between grain boundary segregation and electrical resistivity in dilute nanocrystalline Cu alloys

Abstract The relationships between microstructure, controlled by alloying elements prone to grain boundary segregation, and electrical resistivity in sputtered nanocrystalline Cu were investigated. We find a non-monotonic dependence of the mean grain size on solute concentration for both Cu-Nb and Cu-Fe dilute alloys, with a concentration regime where the grain size increases over that of pure Cu before refining with further alloying. The electrical resistivity follows the same trend, suggesting a non-equilibrium processing route that remarkably gives rise to dilute nanocrystalline Cu alloys with lower resistivity, thermal stability, and enhanced mechanical properties relative to their pure nanocrystalline counterpart.