采用光纤激光对2 mm厚6061铝合金和1 mm厚Q235钢板进行搭接焊, 研究了激光功率、焊接速度和离焦量对焊缝微观组织、接头成分和抗拉剪强度的影响。采用扫描电子显微镜(SEM)对接头截面组织以及拉伸试样断口进行观察, 采用能谱仪(EDS)对断口成分进行分析。结果表明, 激光功率在850 W以上可以形成良好的接头, 最佳焊接速度为35 mm/s, 离焦量为5 mm时焊缝成形最好; 拉伸试样断口主要集中在焊缝-铝合金界面处, 焊缝-Al界面处金属间化合物主要有FeAl3、FeAl、Fe2Al5等, 接头拉伸性能受金属间化合物层厚度影响, 断口为脆性断裂。

Laser welding of Q235 steel to 6061 aluminum alloy were weld by laser in overlap joint. In order to increase the strength, effect of laser power, velocity, defocus was investigated. The microstructure of the specimen under different parameters were observed using scanning electron microscopy and energy disperse spectroscopy. Tensile test was performed. Results obtained show that the best joints can be acquired at 850 W in laser power and 30 mm/s in welding speed. Increasing the focus amount can increase the penetration depth. The brittle phase always occurred at the interface in the joints of different power. The main component is Fe2Al5 phase, FeAl3 phase and FeAl phase.