Effect of micro-friction stir welding parameters on the mechanical properties and microstructure of 5052 aluminum thin sheets

This study utilized high rotational speeds (5500, 8500, and 10,000 rpm) and various traverse speeds (300, 600, and 900 mm/min) to carry out micro-friction stir welding on 0.8 mm thick plates of 5052-0 and 5052-H32 aluminum alloys. The weld heterogeneity was assessed through microstructural analysis and tensile testing under various process parameters. It was found that high rotational speeds generate enough heat to provide grain growth within the stirring zone. Moreover, the stirring zone showed a sizeable population of equiaxed grains, measuring less than 5 mu m, that resulted in an improved mechanical strength of the joint. The joint efficiencies in the 5052-O and 5052-H32 alloys were significantly improved. The joint efficiencies of yield strength for 5052-O and 5052-H32 ranged between 129 and 139%, and 118% and 124%, respectively. The joint efficiencies of tensile strength for 5052-O varied between 102 to 109%, while in 5052-H32 they ranged from 93 to 100%. A comparison of the micro friction stir welding parameter to conventional thick plate friction stir welding showed that the former provided superior properties.