Friction Stir Welding of 6061-T6 Aluminum Alloy

Abstract

Friction stir welding (FSW) is a new and promising welding process which can produce low cost and high quality joints of heat-treatable aluminum alloys. This is because it does not require the consumable filler materials and can eliminate some welding defects such as crack and porosity. The main objective of the present work was to evaluate the processing parameter of friction stir welding (FSW) process for 6061-T6 alloy and to determine the properties of the obtained joints. Experiments have been conducted by varying the friction stir welding processing parameter ; tool rotational speed, in rpm (410, 865, 1140) and feed rate, in mm/min (22, 32, 45). The shoulder diameter of the tool for FSW was 18 mm. Microstructure, microhardness and tensile properties were investigated in this studied. The results showed that there was a variation of grain size in each weld zone which depends on the material and process parameters of FSW in the joint itself. The coarsest grain size was observed in the heat affect zone (HAZ), followed by the Thermo Mechanically Affected Zone (TMAZ) and the nugget zone. The highest hardness was reported on the nugget zone and maximum tensile strength was obtained on the sample with processing parameter 865 rpm rotational speed.