采用光纤激光器对6016车用铝合金与DC56D镀锌钢搭接接头进行了激光焊接试验研究。研究了焊接速度对铝/钢搭接接头熔深、界面金属间化合物和强度的影响，以及单焊缝与双焊缝两种焊缝布置形式的接头强度差异。采用扫描电子显微镜(SEM)和能谱仪(EDS)对焊接接头显微结构、金属间化合物成分以及拉伸断裂试样的断口进行了观察测试。结果表明，选择适当的焊接速度，控制熔深在合适范围内时，可获得较高强度的焊接接头。接头界面处生成的金属间化合物主要有Fe2Al5，FeAl2和FeAl3 3种。采用双焊缝布置形式可有效提高焊接接头强度，接头最大拉剪强度可达155 N/mm，约为铝合金母材抗拉强度的84%，相对单焊缝布置接头提高了26%；拉伸试样断裂在铝合金热影响区处，断裂属于韧窝断裂。

Experimental investigation of fiber laser welding of automotive aluminum 6016 to galvanized steel DC56D in an overlap configuration is carried out. The effect of the welding speed on penetration depth and tensile shear strength of the joints are studied experimentally. On the other hand, the comparison of the joint strength of the single-weld and that of double-weld assemblies is investigated. The microstructure of the joint and the chemical composition of the intermetallic compounds and the fracture of the tensile specimen are investigated by scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) separately. The results indicate that the joint tensile shear strength is great with limiting the penetration depth under appropriate welding speed. The kinds of the intermetallic layer are Fe2Al5, FeAl2 and FeAl3. The double-weld assembly is contributed to improve the joint strength, and the maximum tensile shear strength is 155 N/mm, about 84% of that of the aluminum substrate, which is 26% higher than that of single-weld assembly. In tensile test, the specimen fracture is in heat-affected zone or substrate of aluminum, and the fracture form of the joint is ductile fracture.