中文摘要：

采用电弧辅助激光焊接方法通过添加Al-12%Si焊丝进行了铝/镀锌钢异种金属涂粉对接熔钎焊工艺试验,分析了送丝速度对焊缝成形的影响;运用光学显微镜、扫描电子显微镜、X射线衍射仪、材料试验机等观察分析了焊接接头各区域的微观组织、断口形貌、物相成分和接头力学性能。结果表明：在适当的焊接参数和工艺条件下,能够得到正反面成形良好的对接接头。当焊接速度一定时,随着送丝速度的增大,焊缝正面的铺展宽度减小,背面的铺展宽度增大。Si元素主要富集在接头上部,焊缝中的组织主要有α（Al）基体及沿晶界分布的Al-Si共晶相。铝/钢界面层生成了不均匀的金属间化合物层,其主要物相有Al8Fe2Si、Fe4Al（13）和Fe2Al5,接头最大抗拉强度可达130 MPa,断口表面形貌呈现韧性和脆性共存的混合型断裂特征。

英文摘要：

By means of arc-assisted laser welding and with the addition of Al-12GSi welding wire, the butt welding- brazing experiment of dissimilar metals joining aluminum alloy to galvanized steel sheet with filler powder is conducted. The influence of wire feeding speed on weld appearance is discussed. The microstructure, fracture morphology, phase composition, and mechanical property of welded joints are investigated by means of optical microscope, scanning electron microscope, X-ray diffractometer, and material testing machine. The results show that under suitable welding parameters and process conditions, a welding-brazing joint with high quality appearances at both front and back sides can be obtained. When the welding speed is fixed, with the increment of wire feeding speed, the spreading width of welds at the front side decreases, while that of the back side increases. Si element enriches mainly in the upper part of joints, and the welded seams consist of a（A1） substrate and AI-Si eutectic phases along grain boundaries. A kind of non-uniform intermetallic compounds is formed in the A1/steel interface layer which consists of A18Fe2Si, Fe4All3 , and Fe2Als. The maximum tensile strength of joints is up to 130 MPa, and the surface morphology of fractures possesses a ductile and brittle hybrid characteristic.