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采用光纤激光和铝硅焊丝对2.5mm厚6013铝合金和镀锌低碳钢的异种金属对接接头进行了激光填丝熔钎焊。采用光学显微镜、扫描电子显微镜(SEM)和能谱仪(EDS)分析了熔钎焊对接接头的微观组织,采用拉伸试验测试了接头强度,并研究了热输入对钢/焊缝界面处金属间化合物和接头强度的影响。试验结果表明,在适当焊接参数下可以获得成形良好和具有一定抗拉强度的钢/铝对接接头。进一步分析表明,钢/焊缝界面处主要生成了FeAl2和FeAl3金属间化合物。随着热输入量的增加,金属间化合物的厚度随之增加。焊缝中的组织则为α-Al基体晶界上均匀分布着条状Al-Si共晶组织。在钢板采用30°坡口时可以获得的最大抗拉强度为88MPa,采用45°坡口时强度可以达到135MPa。
The laser welding of the dissimilar metal butt joints of 2.5 mm thick 6013 aluminum alloy and galvanized mild steel was carried out by using fiber laser and aluminum silicon wire. The microstructure of welded butt joint was analyzed by optical microscope, scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). The tensile strength was tested by tensile test. The effects of heat input on the microstructure of the steel Inter-compound and linker strength effects. The experimental results show that steel / aluminum butt joints with good forming and tensile strength can be obtained with proper welding parameters. Further analysis showed that FeAl2 and FeAl3 intermetallics were mainly formed at the steel / weld interface. As the heat input increases, the thickness of the intermetallic increases. The microstructure of the weld is the strip Al-Si eutectic structure uniformly distributed on the grain boundaries of α-Al matrix. The maximum tensile strength that can be obtained when using 30 ° bevel in steel plate is 88MPa, and the strength can reach 135MPa when using 45 ° bevel.