In this study, we focused on graphene reinforced Al-based nano composite bulk materials. In order to disperse graphene around Al powders with average diameter of Al about 100 nm, ultrasonic vibration method was applied with isopropyl alcohol as a solvent before sintering composite materials. The powder before press sintering was prepared to dry in a furnace at about 340 K for 40 minutes. The composite materials with uniform dispersion of graphene were fabricated by with piston-cylinder type press apparatus under the condition of the applied pressure of 3t and the temperature of 723 to 823 K for 4 h in Ar gas atmosphere. We investigated the optimal condition of the composite materials as changing dispersion time by ultrasonic vibration from 1 to 6 h. And we also investigated the optimal condition of the composite materials as changing composition rates from 0 to 3.0 wt%graphene. In our results, vickers hardness of the composite material at 1.0 wt%graphene, dispersion time of 2 h and sintering temperature of 823 K showed the maximum value of 323 Hv, and the density was 2.45 g/cm^3. So, the specific strength increased up to 414 kN・m/kg. It is about 1.4 times bigger than that of Al material. Therefore, graphene reinforced Al-based nano composite materials give us dreams of development for innovative materials.
