A Study on Friction Stir Welding of Al6061-ZrB 2 Metal Matrix Composites

Over the past few decades, various attempts have been made in fabricating aluminum matrix composites (AMCs) reinforced with several ceramic particles for various applications in aircraft, automotive and marine industries. Al6061 reinforced with (10 wt%) ZrB2 composite is a metal matrix composite (MMC) manufactured by the in situ salt–metal reaction. Friction stir welding (FSW), a solid-state welding, overcomes the setbacks associated with conventional fusion welding processes. The primary objective of this work is to adapt FSW process in joining Al6061/ZrB2 with various weld parameters like tool rotational speed (1200, 1300, 1400, 1500, 1600 and 1700 rpm), welding speed (20, 30, 40, 50, 60 and 70 mm/min) and axial force maintained between 2.5 and 3.5 kN. With the addition of ZrB2, the properties of Al6061 are highly improved. An attempt has been made to study the mechanical properties and the microstructure of Al6061-ZrB2 MMC welded by FSW method. The evaluation of microstructure in the welded joints showed various zones like welded nugget zone (WNZ), thermomechanically affected zone (TAZ) and heat-affected zone (HAZ). The weld zone was characterized with homogeneously distributed ZrB2 particles. Samples 3 and 4 showed comparatively good mechanical properties than the remaining samples with different weld parameters.