The surface modification of Al by high current Mo ion implantation using a metal vapor vacuum arc (MEVVA) ion source has been studied. A high aluminum content intermetallic compound Al 12 Mo was formed using Mo ion implantation into Al with a current density of 64 μA/cm 2 (the temperature of the sample rises to ∼410 °C ) to a dose of 3×10 17 ions/cm 2 The hardening aluminide layer with a thickness of about 1600 nm was obtained and the hardness of the Al surface increased with increasing the Mo ion dose up to six times larger than that of the unimplanted one. Also, the elastic modulus of the Al surface was increased by the aluminides.