Abstract

Assemblies consisting of aluminum and particle reinforced aluminum composite alloys have wide spread applications in construction and automotive industries. For a successful use of such dissimilar joints, the welds must have sufficient strength and formability. In the present study, 3003-H24 aluminum alloy and 2124/SiC/25p-T4 composite plates were successfully friction stir butt joined by offsetting the high strength plate to retreating side of the tool under tool rotational speed of 900 to 1400 rpm and traversing speed of 40 to 125 mm/min, keeping other parameters constant. Ultimate tensile strength, percentage elongation and joint efficiency values of the welded joints and hardness variations across the weld interface were determined. The integrity of the joints was investigated using optical microscopy, scanning electron microscopy and energy dispersive spectroscopy. Results indicated that the high quality welded joints could be obtained when a tool rotational speed of 900 rpm and a traverse speed of 125 mm/min were employed. The maximum tensile strength value obtained was about 182 MPa, which corresponds to a joint efficiency of 104% of that of the aluminum alloy base metal.

Key words: Friction stir welding, dissimilar joint, microhardness, mechanical properties.