Microstructural and Mechanical Properties Analysis of Fibre Laser Welding of Dissimilar AA6061 and AA2024 Aluminium Alloy

Abstract

AbstractThe present research work evaluates the butt joints of 2-mm-thick dissimilar aluminium alloy plates AA6061 and AA2024 were welded using a 2 KW laser fibre welding machine. The impact of different laser power on the evaluation of microstructure, phase and mechanical properties has been examined. According to this analysis, low laser power leads to insufficient heat diffusion and defective surface morphology. Maximum tensile strength of 189.1 MPa was achieved with 1.6 KW of laser power, which is approximately 67.5% of the tensile strength of AA6061 Al alloy. Weld zone near the side of AA2024 Al alloy had the highest hardness value, while the HAZ near the side of AA6061 Al alloy had the lowest hardness value. The XRD pattern verified the presence of Al phase and Mg2Si in laser welding joints. The analysis of microstructural shows that grain size in the fusion region becomes finer than the heat-affected region and reference Al alloy. Hence, it is necessary to evaluate the weldabilities of these materials due to their use of aluminium alloys in many manufacturing processes.KeywordsLaser weldingDissimilar aluminium alloysMicrostructure and tensile properties