汽车制造时将钢/铝合金结合起来使用, 能够实现车身强度不降低的前提下, 极大地减轻车身的质量, 以实现节能减排的目的。选取100 mm×50 mm×1.5 mm的DC01冷轧钢板和相同尺寸的6010铝合金进行光纤激光搭接焊接试验。试验发现, 当激光功率P=1 900 W, 焊接速度v=45 mm/s, 离焦量f=-3 mm时获得的焊接接头剪切强度达到最大值100.21 MPa。随后在搭接面添加0.2 mm的Cu中间层后, 实验结果表明, 添加Cu中间层后接头强度提升到144.91 MPa, 焊缝中心硬度显著提高。金相显微镜观察表明, 添加Cu中间层可以增大焊缝深宽比, 同时细化晶粒。XRD结果表明, 添加中间层后有新物相生成, 主要为Al-Cu系化合物。EDS线扫描结果发现, 添加中间层后金属间化合物层由40 μm降低至20 μm。

When the automobile is manufactured, the steel/aluminum alloy is used in combination, and the quality of the vehicle body can be greatly reduced under the premise that the strength of the vehicle body is not lowered, so as to achieve the purpose of energy saving and emission reduction. A fiber laser lap welding test was carried out by selecting a DC01 cold-rolled steel sheet of 100 mm × 50 mm × 1.5 mm and a 6010 aluminum alloy of the same size. It was found that the shear strength of the welded joint obtained when the laser power P=1 900 W, the welding speed v=45 mm/s, and the defocusing amount f=-3 mm reached a maximum value of 100.21 MPa. A 0.2 mm Cu intermediate layer was added to the lap joint. The test results show that the joint strength increases to 144.91 MPa after the addition of Cu intermediate layer, and the hardness of the weld center was significantly improved. Metallographic microscopy observations indicate that the addition of Cu intermediate layer can increase the aspect ratio of the weld and refine the grains. The XRD results showed that a new phase is formed after the addition of the intermediate layer, mainly an Al-Cu compound. The EDS line scan finds that the intermetallic compound layer was reduced from 40 μm to 20 μm after the addition of the intermediate layer.