超声辅助铝/钛搅拌摩擦搭接接头的成形和组织

Formation and microstructure of ultrasonic-assisted friction stir lap welding dissimilar Al/Ti alloys

关键词:  超声|搅拌摩擦搭接|钩状缺陷|金属间化合物

Key words:  ultrasonic|friction stir lap welding|defect|intermetallic compounds

摘要:

借助超声波辅助的方法对铝/钛异种合金进行搅拌摩擦搭接，研究超声波作用对接头的成形和组织的影响. 结果表明，当超声波施加在铝板时，接头的钩状缺陷较高，且会出现孔洞缺陷；当超声施加在钛板时，接头无缺陷. 超声振动能够增大铝/钛界面扩散层的厚度，对接头性能的提高起到一定的促进作用. 当搅拌头转速为300 r/min时，界面扩散层厚度较薄；当搅拌头转速升高至500 r/min时，界面生成一层厚度约为1 μm的金属间化合物. 超声辅助焊接可明显提高接头的断裂载荷.

Abstract:

This work used ultrasonic-assisted friction stir lap welding to join dissimilar Al/Ti alloys. The effect of ultrasonic vibration on joint formation and microstructure was mainly studied. Results show that void appeared inside the joint when the ultrasonic vibration was applied on the Al sheet. Defect-free joint was obtained when the ultrasonic vibration was applied on the Ti sheet. Ultrasonic vibration could enhance the diffusion at the Al/Ti interface, which was beneficial for joint mechanical properties. The thickness of the diffusion layer was rather thin at the rotating speed of 300 r/min. An intermetallic compound with a thickness of 1 μm was obtained at the rotating speed of 500 r/min. The application of ultrasonic could significantly increase the failure load of the joint.