镀锌钢/铝合金激光熔钎焊接头组织及力学性能  

Study on Microstructure and Mechanical Properties of Laser WeldingBrazing Joint of Galvanized Steel/5052 Aluminum Alloy

作　　者：陈大林 赵青山 CHEN Dalin;ZHAO Qingshan(Lanzhou Petrochemical Polytechnic,Lanzhou 730060,China)

机构地区：[1]兰州石化职业技术学院,甘肃兰州730060

出　　处：《电焊机》2022年第4期95-99,共5页Electric Welding Machine

基　　金：甘肃省教育厅资助项目(2019A-198);兰州石化职业技术学院科研项目(KJ2019-16)。

摘　　要：为实现铝/钢异种材料的有效连接,采用激光熔钎焊对厚度均为2 mm的镀锌钢/5052铝合金进行搭接试验(铝上钢下)。随着激光功率的增大(2 400~2 800 W),焊缝抗剪强度先增大后减小;激光功率为2 400 W、2 500 W时,有未焊透、未熔合等缺陷;激光功率为2 600 W时抗剪强度达到最大值164.4 MPa,焊缝无表面缺陷、成形较好;激光功率为2 800 W时,试板被烧穿。对2 600 W搭接接头进行组织形貌、SEM、EDS及力学性能分析。研究表明,接头无气孔、夹渣、裂纹等明显缺陷,实现了铝/钢两种金属的有效连接;焊缝区域主要为Zn的固溶体,接头界面处存在Fe2Al5、FeAl等金属间化合物,金属间化合物厚度小于10μm。接头断口形貌有大面积河流状和台阶状的撕裂棱,为脆性断裂。In order to achieve effective joining of aluminum and steel dissimilar materials, laser welding-brazing is used for lap joint test on galvanized steel/5052 aluminum alloy with thickness of 2 mm( aluminium on top and steel on the bottom).As the laser power increases(2 400 to 2 800 W), the shear strength of the weld first increases and then decreases;when the laser power is 2 400 W and 2 500 W, there are defects such as non-penetration and non-fusion;when the laser power is 2 600 W,the shear strength reaches the maximum value of 164.4 MPa, and the weld has no surface defects and is well formed;when the laser power is 2800 W, the test plate is burnt through. The microstructure, SEM, EDS and mechanical properties of 2 600W lap joint were analyzed. Studies show that the obtained lap joints have no obvious defects such as pores, slag inclusions,cracks, etc. and an effective joining of aluminum and steel is realized;the weld area is mainly Zn solid solution,and there are intermetallic compounds such as Fe2Al5 and FeAl at the joint interface, the thickness of which is less than 10 μm. The fracture morphology of the joint has a large area of river-like and step-like tearing edges, which are brittle fractures.

关 键 词：铝/钢异种金属 激光熔钎焊 金属间化合物 抗剪强度 

分 类 号：TG456.7[金属学及工艺—焊接]