In this study, nanosized B4C and graphite-reinforced ZA27 matrix hybrid nanocomposites were produced with mechanical milling followed by hot pressing. The friction coefficient values of nanocomposite samples remarkably decreased from 0.5036 (+/- 0.085) to 0.2575 (+/- 0.021) with the increase of milling time to 24 hours for nanocomposite powders. That was almost two times lower than those of unmilled nanocomposites. It was determined that the good distribution of reinforcement particles in the microstructure and low grain size allowed the formation of a protective oxide layer against corrosion. The corrosion resistance of the nanocomposite materials obtained from nanocomposite powders milled for 24 hours was quite superior to the others. The results revealed that the corrosion rate values were 29.068 and 4.033 mpy for hybrid nanocomposite samples produced from unmilled and milled powders for 24 hours, respectively.