7050高强铝合金搅拌摩擦焊典型宏观缺陷试验研究

目的 研究7050铝合金搅拌摩擦焊接头中隧道缺陷及未焊透缺陷的行程规律及其对接头性能的影响。方法 采用预制间隙、改变搅拌针长度等方法获得了搅拌摩擦焊隧道缺陷及未焊透缺陷，通过金相分析、力学性能测试对缺陷及接头性能进行了分析。结果 相比隧道缺陷，根部未焊透缺陷对接头性能的影响更大，压入量对隧道、未焊透缺陷有重要影响，板厚5 mm，搅拌针长度小于4.8 mm时，未焊透缺陷对接头性能将产生显著影响。结论 应严格控制搅拌针长度及压入量，避免根部未焊透缺陷对接头性能的影响。

Experimental Study on Typical Macroscopic Defects of 7050 High Strength Aluminum Alloy Friction Stir Welding

This paper aims to study the stroke rule of tunnel defect and incomplete welding of 7050 high strength aluminum alloy friction stir welding and their influences on the joint property. The defects of friction stir welding tunnel and incomplete welding were obtained by means of prefabricating gap and changing the length of probe. The defect and performance of joint were analyzed through metallographic analysis and mechanical property test. The results showed that, compared with tunnel defects, lack of penetration had a greater impact on the joint performance; and the amount of pressure had an important impact on the tunnel and lack of penetration defects. When the plate thickness was 5 mm and the length of probe was less than 4.8 mm, lack of penetration defects would have a significant impact on the joint performance. The results show that the length of stirring needle and the amount of pressing should be strictly controlled to avoid the influence of root defect on joint performance.