Microstructures and properties of welded joint of aluminum alloy to galvanized steel by Nd:YAG laser + MIG arc hybrid brazing-fusion welding  

铝合金/镀锌钢板Nd:YAG激光+MIG电弧复合热源熔-钎焊接头的组织与性能(英文)

作　　者：秦国梁[1] 苏玉虎[1] 王术军[1] 

机构地区：[1]山东大学材料液固结构演变与加工教育部重点实验室,济南250061

出　　处：《Transactions of Nonferrous Metals Society of China》2014年第4期989-995,共7页中国有色金属学报（英文版）

基　　金：Project (50905099) supported by the National Natural Science Foundation of China;Project (20090131120027) supported by the Specialized Research Fund for the Doctoral Program of Higher Education,China

摘　　要：According to the differences in melting point between aluminum alloy and steel, 6013-T4 aluminum alloy was joined to galvanized steel by large spot Nd：YAG laser ＋ MIG arc hybrid brazing-fusion welding with ER4043（AlSi5） filler wire. The microstructures and mechanical properties of the brazed-fusion welded joint were investigated. The joint is divided into two parts of fusion weld and brazed seam. There is a zinc-rich zone at fusion weld toe, which consists of α（Al）-Zn solid solution and Al-Zn eutectic. The brazed seam is the Fe-Al intermetallic compounds （IMCs） layer of 2-4μm in thickness, and the IMCs include FeAl2, Fe2Al5 and Fe4Al13. FeAl2 and Fe2Al5 are located in the compact reaction layer near the steel side, and Fe4Al13 with tongue shape or sawtooth shape grows towards the fusion weld. The tensile strength of the joint firstly increases and then decreases as the welding current and laser power increase, the highest tensile strength can be up to 247.3 MPa, and the fracture usually occurs at fusion zone of the fusion weld. The hardness is the highest at the brazed seam because of hard Fe-Al IMCs, and gradually decreases along the fusion weld and galvanized steel, respectively.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。

关 键 词：brazing-fusion weldingi welding of dissimilar metals hybrid welding mechanical properties intermetallic compounds 

分 类 号：TG454[金属学及工艺—焊接] TG407