In this paper,we report the use of blowing nitrogen gas for the successful fabrication of a composite layer composed of Ti/TiN on a substrate of commercially pure titanium (cp-2) using the friction stir processing technique.The prepared composite layer was characterized by X-ray diffraction,scanning electron microscopy and energy-dispersive X-ray spectrometry.The maximum microhardness of the Ti/TiN composite reached 1024 HV,which is 6.4 times higher than that of the titanium substrate.The results of wear test indicated that the Ti/TiN composite layer possesses excellent abrasive and adhesive wear resistance because of the formation of the TiN and its high hardness.