Friction stir welding of an AA6061/Al2O3/20p reinforced alloy

The main objective of the present work was to establish a friction stir welding (FSW) process parameters envelope for an AA 6061 alloy reinforced with 20% of Al2O3 particles, and determine properties of the obtained joints. After a brief description of the FSW technique, and the difficulties in joining MMCs, experimental procedure is illustrated. Microstructure has been observed with optical microscope, and images have been analysed with an image analysis software. Microhardness and tensile tests have been also carried out. The tool’s stirring effect has a substantial influence on the reinforcement particles distribution and shape. Tensile testing revealed joint efficiencies over 80% for the Rp0, 2 and of slightly more than 70% for the Rm, with failure outside the stir zone. The parameter envelope determined in the present study resulted in defect free, high strength welds. Results also indicate that the alloy investigated could be welded with process parameter comparable to those used for its unreinforced counterpart.