Surface Improvement of 7075 Alloy Using Friction Stir Processing

ABSTRACTIn current work, aluminium surface composites were developed via friction stir processing (FSP). AA7075-T6 was reinforced with ultrafine size SiO2 particles to prepare either surface composite or double surface (i.e. sandwich) composite. In addition, AA7075 hybrid surface composites were prepared using ultra- fine size SiO2 and Al2O3 particles. These surface composites were developed using FSP parameters of 600 rpm, 50 mm/min and 3 degrees tilt angle. FSP tool with a square profiled pin of 3.5 mm length and of 5mm side enabled sound surface composites and uniform particle distribution. The developed surface(s) composites were being evaluated using different metallographic techniques to investigate the macro and micro features across the stirring zone. The hybrid surface (SiO2 and Al2O3 particles/ AA7075) composites showed enhancement in particle distribution composites and microhardness measurement compared to AA7075/ SiO2 surface composites. The current results are compared with those from other similar composites reported in the literature.