中文摘要：

搅拌摩擦焊焊缝金属的塑性流动与工件表面状态对焊缝的微观组织演化及焊缝缺陷形成有着十分重要的影响,采用＂示踪铜箔＂探索了可视化示踪材料紫铜箔在搅拌摩擦焊接头内的迁移行为。为进一步分析和证明搅拌摩擦焊接头＂弱连接＂缺陷形成机制,进行了2219铝合金（阳极化处理）的搅拌摩擦焊试验。结果表明,焊件表面未清理的氧化膜在搅拌摩擦接头内形成了一条始于后退侧、而在前进侧取向发生逆向延伸的黑色流动迹线,即＂S＂线弱连接缺陷。

英文摘要：

The flow behavior of plastic deformation metal and surface condition of the welding work piece during the friction stir welding process have a great influence on the evolution of microstructure and welding defects of the welded joint.In this paper,the transfer behavior was studied in the friction stir welding joint by using ‘tracing copper foil’.In order to analyze and test the mechanism of the‘weak-bonding’defects for FSW joint,friction stir welding of anodized 2219aluminum alloys was carried out.The results show that the oxide film forms‘S’line defects which begins with the retreated side of the joint,ends at the advanced side and extends to the nugget zone backward.