采用光纤激光器, 不添加任何填充材料, 对6.0 mm厚5083铝合金和3.5 mm厚低碳钢板材进行激光深熔对接工艺试验, 研究激光偏移量对接头焊缝成形的影响。利用光学显微镜、扫描电镜、显微硬度仪、拉伸试验机等研究接头界面的微观组织、显微硬度和抗拉强度。结果表明, 激光束偏移量Δd由0.3～0.7 mm变化时, 界面金属间化合物从21.0 μm逐渐减小到4.1 μm; 当激光偏移量为0.7 mm和0.3 mm时, 接头界面层的平均硬度分别为765.4 HV和671.3 HV。当激光偏移量为0.6 mm时, 接头抗拉强度强度最高, 平均抗拉强度为107 MPa, 达铝母材的60%。

The laser keyhole welding was carried out onthe butt joints between the Q235 steel sheets with thickness of 3.5 mm and the 6.0 mm thick 5083 aluminum alloy with a fiber laser. The effects of laser distance on the weld shape were investigated. The microstructures and mechanical properties of the joints were investigated by optical microscope, scanning electron microscope,micro-hardness tester and tensile testing machine. Results show that the thickness of intermetallic layer in the interface of the welded joints gradually decreases from 21.0 μm to 4.1 μm with laser distance varies from 0.3 to 0.7mm. When the laser distanceis 0.7 mm and 0.3 mm,the average hardness of the intermetallic layeris 765.4 HV and 671.3 HV, respectively. The maximum tensile strength is 107 MPa when the laser distance is 0.6 mm, which reaches the 80% tensile strength of the 5083 alloys.