2219铝合金静止轴肩搅拌摩擦焊接头组织及性能

摘要

采用静止轴肩搅拌摩擦焊的方法获得了2219C10S铝合金焊接接头,研究了焊接接头典型的宏观、微观组织特征、焊接工艺参数对焊缝成形特征及焊接接头力学性能的影响规律.结果表明:相对常规搅拌摩擦焊,由于静止轴肩式搅拌头的结构特点,焊接过程中可有效避免飞边和焊缝内部缺陷;随着焊速的增加,接头焊核由“碗状”变为“腰鼓”状,体积也逐渐减小,还出现了轴肩影响区这一特殊组织特征;焊接接头的显微硬度分布呈现出独特的“U”形,焊核区的显微硬度最低;当焊接速度≤250mm/min,随着焊接速度的增加,接头的拉伸性能逐渐增加;当焊接速度增加至300 mm/min时,由于在焊接接头中出现了沟槽缺陷,拉伸性能急剧下降.%2219C10S aluminum alloy welded joints were obtained by stationary shoulder friction stir welding (SSFSW).The paper presented the typical macroscopic and microstructural characteristics of welded joints,the influences of welding parameters on the forming characteristics and the mechanical properties of welded joints.The results showed that as compared with the traditional friction stir welding (C-FSW),flash and the defects of the weld could be effectively avoided during welding due to the structural characteristics of the stationary shoulder mixing head.With the increase of welding speed,the joint nuclear changed from "bowl" to "waist drum",and the volume decreased,and the welded joint was also specially characterized with the shoulder-affected zone.The microhardness distribution of the welded joints presented a unique " U " shape,and the nuclear was the lowest.With the increase of welding speed which was under 250 mm/min,structure property increased;when welding speed reached to 300 mm/min,the structure property fell sharply.