Enhancing Microstructural Characteristics and Mechanical Properties in Friction Stir Welding of Thick Magnesium Alloy Plates through Optimization

This research explores friction stir welding (FSW) to examine the mechanical characteristics and microstructure of thick plates manufactured from the Mg-8Al-0.5Zn alloy. Applying the FSW procedure to warm-form an Mg-8Al-0.5Zn alloy for the differential case covering the gears in the car’s automotive technology. Weld quality was significantly improved after using response surface methodology (RSM) to examine various welding parameters and find the best configurations. Improved grain refinement and phase distribution in the weld zone were found in the microstructural study of 11.5 mm thick magnesium alloy plates using RSM-optimized parameters. By dynamic recrystallization, the grain size was reduced to 16 μm, which is fifteen times smaller than the original material, thanks to the good results of single-pass FSW welding. Welding results showing high-quality characteristics such as tensile strength (161.8 MPa), elongation (27.83%), and joint efficiency (98.96%) were achieved using the ideal rotating speed of 800 RPM and traverse rate of 100 mm/min. In addition, the nugget area showed a notable 14.3% rise in micro-hardness. The research concludes that the Mg-8Al-0.5Zn alloy can be effectively welded utilizing FSW parameters, leading to an enhanced microstructure and remarkable mechanical capabilities. This proves that this technology is viable for thick magnesium alloy plate welding.