Recently friction stir processing (FSP) was developed as a generic tool for microstructural modification based on the basic principles of FSW. In this case, a rotating tool is inserted in a workpiece for localized microstructural modification for specific property enhancement. In this research, FSP was used to develop in-situ Al-Cr-O hybrid nanocomposite on the surface of Al6061 plate. A new procedure was introduced for applying the reinforcement particles, in which Cr2O3 powder was applied on Al6061 plate by atmosphere plasma spray and then the FSP was performed on the plate. In order to optimize the FSP parameters, microstructural and mechanical evaluations were performed. The optimized parameters including tool rotational speed ( ) and tool travelling speed ( ) were determined to be 630 rpm and 100 mm/min respectively. In order to evaluation the effects of the friction stir processing on mechanical and tribological behavior, tensile, hardness and wear tests were performed on base metal, FS processed and nanocomposite samples. Dominating wear mechanisms were investigated by surface examination of and studying of wear products using scanning electron microscopy (SEM). Microstructur of nanocomposite was investigated by scanning electron microscopy and transmission electron microscopy (TEM). Phase analysis was perfomed with X-ray diffraction (XRD) and energy dispersive spectrometer (EDS). R. . result of reaction between Al and Cr. With respect to the results, reaction mechanism in FSP was suggested. nanocomposite, Friction stir processing, Al-Cr intermetallics, Mecmeical properties, wear.
