Aluminum alloys L2, LD2, LF12, LY12, and Al-4% Cu were implanted at room temperature with nitrogen ions at an energy of 80 keV and dose range of 1 X 10(16) - 8.3 x 10(17) N+ cm-2. The surface structure and chemical state of the implanted surface layer was investigated by x-ray photoelectron spectroscopy, transmission electron microscopy and transmission electron diffraction. Hardness measurements were made using a Vickers microhardness tester, and wear tests were carried out using a pin-on-disk wear testing machine. The results reveal that implanted nitrogen combines with aluminum to form AlN precipitates at room temperature and nitrogen implantation accelerates the aging process of Al-4% Cu alloys. The results also reveal that nitrogen implantation increases the hardness and sliding wear resistance of aluminum alloys. The improvements are mainly attributed to the formation of AlN precipitates.