高温钎焊和电阻钎焊纯铝接头的微观组织及性能对比  

Comparison of Microstructure and Properties of High Temperature Brazed and Resistance Brazed Pure Aluminium Joints

作　　者：李翠 董晓利 武晓军 肖磊 LI Cui;DONG Xiaoli;WU Xiaojun;XIAO Lei(Xinjiang Industrial Vocational and Technical College,Urumqi 830000,China)

机构地区：[1]新疆工业职业技术学院,新疆乌鲁木齐830000

出　　处：《电焊机》2022年第3期72-77,共6页Electric Welding Machine

摘　　要：铝具有强度高、塑性好、抗腐蚀性能优异等特点,广泛应用于汽车工业中,但是传统的钎焊并不能实现纯铝的有效连接,因此考虑电阻钎焊的方法。对比高温钎焊和电阻钎焊纯铝接头的微观组织形貌和力学性能,采用两步电阻钎焊方法,在第一步施加1 s+3 kA的电流,在第二步施加6 s+6 kA的电流,以获得连接性能良好的钎焊连接层。结果表明,高温钎焊接头的连接层中晶粒呈现粗大的树枝状晶,电阻钎焊接头的连接层晶粒则呈现圆形的等轴状晶;且电阻钎焊接头的断面是韧性断裂和解理断裂交杂的混合型断裂模式;同时由于电场的施加,增多了连接层中异质形核结点,抑制了枝晶的生长,最终得到晶粒细小的钎焊接头,抗拉强度达到65.79 MPa。Aluminum is widely used in the automotive industry due to its high strength,good plasticity,and excellent corrosion resistance.However,traditional brazing cannot achieve effective connection of pure aluminum,so resistance brazing is considered.Compare the microstructure morphology and mechanical properties of high-temperature brazing and resistance brazing aluminum alloy joints.Two-step resistance brazing method is adopted.In the first step,a current of 3 kA is applied for 1 s,and a current of 6 kA is applied for 6 s in the second step.In order to obtain a brazing connection layer with good connection performance.The results show that the grains in the connecting layer of high-temperature brazing joints present coarse dendrites,while the grains of the connecting layer of resistance brazing joints present round equiaxed crystals;and the section of resistance brazing joints is ductile fracture.The mixed fracture mode of reconciliation and cleavage fracture;at the same time,due to the application of electric field,the heterogeneous nucleation nodes in the connecting layer are increased,the growth of dendrites is inhibited,and the brazed joints with fine grains are finally obtained,and the ultimate tensile strength reaches 65.79 MPa.

关 键 词：电阻钎焊 韧性断裂 解理断裂 异质形核 

分 类 号：TG457.14[金属学及工艺—焊接]