Optimization of friction stir welding process parameter in the joining of AA7075-T6/AA5083-O dissimilar aluminum alloy using response surface methodology

This present study is aimed to produce high-strength dissimilar joints of AA5083-O and AA7075-T6 alloys through optimization in the friction stir welding (FSW) process parameters. In this work, we have employed the response surface methodology (RSM) iteratively to generate 20 different welding process parameter combinations. These parameters are used to manufacture dissimilar weld joints, and the impact of these process parameters on the mechanical properties of the weld joints is evaluated by performing a series of mechanical tests such as tensile and microhardness. The microstructural evolution of the welded joints is studied using optical and SEM techniques. EBSD analysis is performed to understand the grain size, orientation, and changes in microstructure. The weld nugget zone reveals the presence of finer grains measured as 0.3 mu m-0.7 mu m. The specimen manufactured using FSW optimized process parameters of rotational speed 1100 rpm, welding speed 50 mm/ min, and tool tilt angle 2 degrees shows the ultimate tensile strength of 417 MPa, weld nugget hardness of 189 HV0.1, and weld efficiency 80.65%. The tensile fractured surface of specimens is also inspected using SEM to determine the mode of failure reached in the welded joints. (c) 2001 Elsevier Science. All rights reserved.