Characteristic of copper matrix simultaneously reinforced with nano- and micro-sized Al2O3 particles

► Copper matrix was reinforced with nano- and micro-sized Al2O3 particles. ► The twofold role of coarse Al2O3 particles in matrix strengthening exists. ► During shorter milling time these particles contribute to increase of microhardness. ► At longer milling time decrease in microhardness is related to recrystallization.