الفهرس 
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Abstract
Metal Matrix Composites materials reinforced with ceramic powder have the advantages of high strength, high wear resistance, light weight and high elastic modulus compared to unreinforced materials which increases their importance in sensitive industries. In this study, a surface composite has been developed by incorporation of SiC powder into surface of AA 5083 via friction stir processing (FSP) technique. A friction stir processing tool of a cylindrical probe shape rotated at a speed of 400 rpm and 1000 rpm was plunged into the workpieces and moved along the groove at a travelling speed of 20 mm/min and 40 mm/min. A number of friction stir processing passes was applied in order to improve the distribution of SiC powder. The effect of FSP passes and changing of the processing parameters on homogeneity of SiC particles in the metal matrix have been evaluated by macrostructure, microstructure, X – ray diffraction, hardness of cross-section, and wear test. An optimization of FSP parameters was conducted for good microstructural and mechanical properties. Compared to the as-received AA 5083, Vicker’s Hardness value was increased to 110 HV. The wear resistance of the surface for the friction stir processed samples was improved. It was found that increasing the number of processing passes of friction stir processing assists to a better distribution of SiC particles which lead to improve the properties of the surface composite. Another important factor which obviously affect the distribution of SiC in the alloy is the rotation rate of the tool. The wear properties of the as – recieved AA5083 was improved by addition of ceramic powder (SiC) as a rainforcement in a uniform manner. The wear rate was reduced from 0.0001 g/m for the base metal to 0.00001 g/m for FSPed specimen produced by the optimum conditions.