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基于铝合金和镀锌钢在熔点上的差异,以ER4043(AlSi5)为填充材料,采用大光斑Nd:YAG激光+MIG电弧复合热源焊接工艺实现两者的熔-钎焊接,研究熔钎焊接头组织和性能。铝合金/镀锌钢板熔钎焊接头分为熔焊接头和钎焊缝两部分,熔焊缝组织由α(Al)等轴晶和晶界上短棒状的Al-Si共晶组织组成,焊趾处的富锌区为α-Al-Zn固溶体和Al-Zn共晶组织。钎焊缝为Fe-Al金属间化合物层,厚度为2~4μm,金属间化合物包括FeAl2、Fe2Al5和Fe4Al13,其中FeAl2和Fe2Al5位于近钢侧的紧密层,而Fe4Al13则呈舌状或锯齿状向熔焊缝内生长。接头抗拉强度随着焊接电流和激光功率的增大呈先增大后减小的趋势,最高可达247.3 MPa。拉伸断裂位置一般位于熔焊缝的熔合区,为以韧性断裂为主的混合断裂。接头内硬度的最大值位于钎焊缝处,然后分别沿着两侧钢板和铝合金熔焊缝逐步降低。
Based on the difference of melting point of aluminum alloy and galvanized steel, ER4043 (AlSi5) was used as the filler material, and the large spot Nd: YAG laser + MIG arc heat source welding process was used to realize the fusion welding between the two. Joint organization and performance. Melt-welded joints of aluminum alloy / galvanized steel are divided into two parts: welded joints and brazed joints. The welded joints are composed of α (Al) equiaxed grains and Al-Si eutectic microstructures with short rods on the grain boundaries. The zinc-rich zone at the toe is an α-Al-Zn solid solution and an Al-Zn eutectic structure. The brazing seam is an Fe-Al intermetallic compound layer with a thickness of 2~4 μm. The intermetallic compounds include FeAl2, Fe2Al5 and Fe4Al13, in which FeAl2 and Fe2Al5 are located in the close layer on the near steel side, while Fe4Al13 has a tongue-like or jagged Weld weld growth. The tensile strength of the joint first increases and then decreases with the increase of welding current and laser power, up to 247.3 MPa. Tensile fracture location is generally located in the weld fusion zone, as the ductile fracture-based mixed fracture. The maximum hardness of the joint is located at the brazing seam, and then gradually decreased along the weld on both sides of the steel plate and aluminum alloy.