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

Abstract

Abstract This study examined micro-friction stir welds in aluminum alloys 5052-0 and 5052-H32, using 0.8 mm thick sheets. The analysis aimed to evaluate weld heterogeneity across various process parameters through microstructural examination and tensile testing. The findings suggested that elevated rotational speeds cause more heat input, resulting in adequate energy for grain growth within the stirred zone. A substantial number of equiaxed crystals that were less than 5 μm in size were observed in the stirred zone. Moreover, the number of these crystals increased with an increase in the rotational speed. The interaction of high strain rate and heat input promotes grain growth, but its effect is limited by grain size and agitator pin speed. The yield strength joining efficiencies of 5052-O and 5052-H32 range from 136% to 156% and 103% to 112%, respectively. Similarly, the tensile strength joining efficiencies range from 75% to 82% and 92% to 100%, respectively. The micro friction stir welding parameter was found to provide superior properties compared to conventional thick plate friction stir welding.