Investigation on Mechanical and Tribological Behavior of Double Pass Friction Stir Welded Aluminium Joints

The unreinforced and reinforced joints were fabricated with commercially available and artificially aged aluminium alloys AA 6061 and AA 7075 via friction stir welding process. Hexagonal boron nitride, a wear resistant and a good lubricant nano material was chosen as the reinforcement. Three spindle speed (600, 800 and 1000 rpm), constant tool traversing speed of 40 mm/min and tool with cylindrical pin geometry were selected as the welding parameters for the present study. Double pass welding and 5 vol% of nano particles were kept constant for all the experimental trial runs. The welded samples were investigated for mechanical traits and microstructural characterization using field emission scanning electron microscopy and energy dispersion spectroscopy techniques. The study affirmed that the reinforced particles played a dominant role in establishing grain refinement across the stirred zone. Four pins from the parent alloys, unreinforced and reinforced weld samples were subjected to wear morphology. The reinforced weld exhibited better wear resistant property compared to parent and unreinforced ones.