Friction Stir Welding Of 7075 Aluminum Alloy And AZ31B Magnesium Alloy And H68 Brass

Friction Stir Welding (FSW) is a new solid-state plastic joining process. Because of its good performance connectors, low-defect, high strength, etc.. This is commonly used in industry to connect heterogeneous materials have great potential for application.This paper focuses on technology and welding performance of 7075 Aluminum alloy and AZ31B magnesium alloy, 7075 Aluminum alloy and H68 brass dissimilar friction stir welding.The results show that the joint of dissimilar friction stir welding has four regions: the base metal zone, heat-affected zone, thermo mechanically affected zone and weld nugget zone. Weld nugget zone grain refinement, for obvious recrystallization equiaxed grain, dissimilar material by lamellar-like and vortexe shape very good interweaving in the same place, advancing side and retreating side not entirely symmetrical.The butt-welded joints of 7075 aluminum alloy and AZ31B magnesium alloy possess Mg-rich and Al layered structure of the dynamic recrystallization. XRD, SEM and EDS analysis show that the weld nugget contains a lot of Al₁₂Mg₁₇ and Al₃Mg₂ diffraction peak, which indicates that the intermetallic compounds of the two materials were formed during the welding processing. Micro-hardness values fluctuations, ranging from 50.73 to 153.48. There are intermetallic compounds in the spiral structure and the lamellar structure, which leads to the weld having a higher hardness value.The lap joints of 7075 aluminum alloy and H68 brass has not formed intermetallic compounds. microhardness analysis of brass and aluminum show that the weld nugget zone of microhardness value was significantly higher than the base material, Which is due to fine grain structure and dislocation that were formed during dynamic recrystallization of friction stir welding process. we can obtain the good appearance and defect-free brass and aluminum alloy lap joint when selecting the appropriate parameters.