Fabrication of Surface Metal Matrix Composite of AA7075 using Friction Stir Processing

Friction stir processing (FSP), derived from the friction stir welding (FSW) process, is an emerging novel, green and energy-efficient processing technique to fabricate surface composite. The FSP technique has been used in the present investigation to fabricate surface composites, using Aluminium Alloy 7075 as parent metal and Titanium Dioxide and Silicon Carbide powder particles as reinforcement. Aluminium Alloy 7075 has been selected as the matrix phase, as being widely used by the automotive and aerospace application and has the highest strength among all commercial Al alloys. The present work details the fabrication of surface composites using various reinforcement combinations like AA7075- TiO2, AA7075- and AA7075- SiC, TiO2+SiC at constant tool rotation, tool travel speed and the number of passes have been discussed. The same being intended to improve hardness and thereby wear resistance. The fabricated surface composites are examined for microstructure using an image analyzer and found friction stir processed zone with fine microstructure than the base material. It is also observed that the average hardness of friction stir processed surface composite was higher than that of parent metal. Wear Resistance is found to be improved compared to the parent metal. It is found that Tensile strength is also enhanced than the base material.