Magnesium AZ31B-0 alloy being considered as extremely attractive lightweight materials for a wide range of the army's future applications where weight reduction is a critical requirement because of its low density. Furthermore, magnesium has good vibration damping capacity. Magnesium alloys have the advantages of low density, high specific strength and excellent damping characteristic, and have become potential structural materials in aerospace and automobile manufacture fields. Magnesium is also highly flammable when it is powdered or shaved into thin strips (such as flash resulting from a weld). The selected material was welded with Friction Stir Welding using combination of different parameters i.e. tool rotational speed (900 rpm, 1200 rpm, 1500 rpm, 1800 rpm and 2100 rpm) and constant welding speed of 45 mm/min. a cylindrical left hand threaded tool with 21 mm tool shoulder diameter and 7 mm pin diameter was employed for welding. The effect of tool rotational speed was examined on the mechanical properties. Microhardness decreases with increase in tool rotational speed due to high heat input. It was observed that excessive heat generation and insufficient flow of plasticized material at higher values of tool rotational speed, leading to formation of defects which ultimately results in failure of weld joints between Stir Zone and Thermo mechanically affected Zone.
Friction Stir welding, Stir Zone, Ultimate tensile strength, Advancing side (AS) Heat affected zone (HAZ)
