Numerical assessment of temperature and stresses in friction stir welding of dissimilar Mg-Al-Zn alloys

ABSTRACTMagnesium (Mg) alloys are used more frequently as a replacement for heavier structural materials because of their advantageous specific strength and eco-friendly attributes. Their fusion welding is a difficult process, but the friction stir welding (FSW) offers a potential solution to these issues. In this study, a thermal analysis is carried out to obtain the temperature distribution and residual stresses related to FSW of different Mg-Al-Zn series Mg alloys under different processing conditions. The highest temperature recorded at the centre of the weld was 544.04°C, while the average von Mises stress during welding was 185.07 MPa. These values were achieved with a tool rotational speed of 1000 rpm, welding speed of 40 mm/min, and a tool shoulder diameter of 21 mm. The temperatures obtained through the numerical model were validated by comparing them with experimental data. During the experimental analysis, small cracks were observed at the centre of the welded joint, resulting from the formation of MgO. The welded joint exhibited a maximum tensile strength of 234.86 MPa, which is approximately 90% of the stronger AZ31 Mg alloy.KEYWORDS: Dissimilar magnesium alloystemperatureresidual stressesmicrostructuretensile strengthfriction stir weldingthermal analysis AcknowledgementsAuthors would like to acknowledge the research assistantship provided by UGC New Delhi, India, and MNNIT Allahabad, Prayagraj, U.P., India (under TEQIP-III scheme).Disclosure statementNo potential conflict of interest was reported by the author(s).Additional informationNotes on contributorsUmesh Kumar SinghUmesh Kumar Singh earned his M.Tech. and Ph.D. from Motilal Nehru National Institute of Technology Allahabad, Prayagraj (Uttar Pradesh), India. He has published research articles in various refereed International Journals and Conferences. His are of research is Friction Stir Welding.Avanish Kumar DubeyAvanish Kumar Dubey earned his M.Tech. and Ph.D. from Motilal Nehru National Institute of Technology Allahabad, Prayagraj (Uttar Pradesh), India. He has published many research articles in various refereed International and National Journals and Conferences. Currently, he is working as a Professor in the Department of Mechanical Engineering, Motilal Nehru National Institute of Technology Allahabad, Prayagraj (Uttar Pradesh), India. His areas of interests are Laser Material Processing and Advanced Manufacturing Processes, Modeling and Optimization of Manufacturing Processes.