7A52铝合金FSW与双丝MIG焊接接头性能比较研究

Comparison of Joint Properties of 7A52 Alloy Welded by Friction Stir Welding and Double Wire MIG

研究了20mm厚的7A52铝合金搅拌摩擦焊和双丝MIG焊接工艺,对比分析了焊接接头的组织与性能。研究表明;对于20mm厚的7A52铝合金,搅拌摩擦焊接头强度比双丝MIG提高15%左右;双丝MIG焊缝区由于焊接时热输入量较大,晶粒长大明显;FSW焊缝区发生动态再结晶,生成细小的等轴晶粒。SEM断口分析表明,双丝MIG与FSW断口均表现为明显的韧窝形貌,FSW的强化相粒子分布于韧窝中,是形成韧窝形微孔的源。

The friction stir welding process and double wire MIG process for aluminum alloy with 20 mm thickness was researched,and the properties and structure of the welded joint was analyzed.The results show that 7A52 aluminum alloy can be welded successfully by FSW and double wire MIG,and the yield strength of FSW is increased by 15% compared with double wire MIG.Due to more welding heat input by double wire MIG,the grain of the weld zone grows bigger.The weld nugget zone of FSW are fine grains which result from the dynamic recrystallization.SEM fracture analysis indicates that,the fracture surface of both double wire MIG and FSW show an obvious dimple morphology,the strengthening phase particles distribute in the dimple,which are the source of dimple-shaped pores.