镁铝异种金属激光-TIG复合热源焊焊接性分析
Microstructure of laser-TIG hybrid welding joint of dissimilar metals of Al and Mg
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摘要: 采用激光-TIG复合热源和TIG焊接异种金属镁和铝,利用X射线衍射仪、金相显微镜和扫描电镜研究镁和铝焊接接头的微观组织、元素分布。结果表明,TIG焊接镁和铝形成连续的金属间化合物层,导致镁和铝接触的界面开裂,不能实现有效的连接。激光-TIG复合热源由于其焊接速度高和对熔池的快速搅拌作用,使镁和铝形成的金属间化合物由连续的层状变成弥散的状态,改善了异种金属镁和铝的焊接性。镁和铝激光-TIG复合热源焊接的焊缝成形均匀,美观。Abstract: TIG and laser-TIG hybrid welding techniques have been used to study the weldability of dissimilar alloys of Al-6061 to Mg-AZ31B. The welded samples were analyzed by metallographic techniques using both optical and scanning microscopy in combination with a X-ray diffraction instrument. It was found that the TIG welding could not make the joint of the dissimilar alloys due to the continuous Mg and Al intermetallic compounds. But the laser-TIG hybrid welding improved the weldability because of its high welding speed and fast stir by laser and arc which make the continuous intermetallic compounds on the interface of Mg and changed into dispersive form. The weld appearance of laser-TIG hybrid welding is uniform.