不同焊接速度下Cu/Al/Cu纳秒激光焊接接头组织及性能研究  

Microstructures and Properties of Nanosecond Laser Welded Cu/Al/Cu Joints Under Different Welding Speeds

作　　者：朱宝华 牛司成 李奇戈 赵曙明 陆兴 檀财旺[3] 宋晓国[3] Zhu Baohua;Niu Sicheng;Li Qige;Zhao Shuming;Lu Xing;Tan Caiwang;Song Xiaoguo(School of Materials Science and Engineering,Harbin Institute of Technology at Shenzhen,Shenzhen 518055,Guangdong,China;Shenzhen JPT Opto-electronics Co.,Ltd.,Shenzhen 518110,Guangdong,China;State Key Laboratory of Advanced Welding and Joining,Harbin Institute of Technology,Harbin 150001,Heilongjiang,China)

机构地区：[1]哈尔滨工业大学(深圳)材料科学与工程学院,广东深圳518055 [2]深圳市杰普特光电股份有限公司,广东深圳518110 [3]哈尔滨工业大学先进焊接与连接国家重点实验室,黑龙江哈尔滨150001

出　　处：《中国激光》2023年第20期25-36,共12页Chinese Journal of Lasers

基　　金：山东省自然科学基金(ZR2021YQ30)。

摘　　要：采用纳秒脉冲激光对铜/铝/铜三层薄片结构进行焊接,分析焊接速度对焊缝成形、微观组织与接头力学性能的影响。结果表明:较低的焊接速度容易引起气孔和裂纹等接头缺陷,较高的焊接速度造成焊缝中的气孔聚集于界面,合适的焊接速度有利于获得良好的熔透深度和较少的缺陷;焊缝中存在Cu Al_(2)、Cu_(9)Al_(4)与Cu_(4)Al_(3)等铝/铜二元化合物,且焊缝中生成的化合物的种类与焊接速度有关;当焊接速度为21 mm·s^(-1)时,界面较少的缺陷和钉状焊缝使得接头具有的最大剪切力为95.1 N。接头发生了三种断裂:焊点撕裂、焊缝剪切+熔核拔出复合断裂以及熔核拔出失效,焊点边缘的裂纹及脆性相是焊点撕裂失效的原因,界面处焊缝边缘的铜/铝化合物和气孔缺陷是复合断裂的原因,较浅的熔深和界面化合物导致了熔核拔出失效。Objective In electronics and precision devices,achieving reliable connections for composite joints of thin metal sheets such as Al/Cu is critical,as this helps reduce Cu usage costs.Conventional welding methods such as brazing and stir friction welding are limited by the sample size and tend to introduce excessive heat input into the joint.Thus,they are not suitable for joining thin metals.Suitable methods for joining thin metal sheets include ultrasonic and laser welding.Laser welding,particularly short-pulse laser welding,has precise heat input,high energy density,and good controllability,making it suitable for connecting thin sheets.Accordingly,in this study,a short-pulse laser is used to weld Cu/Al/Cu laminar joints.The effects of scanning speed on the joint microstructures and properties are investigated to provide guidance in joining laminar metal sheets.Methods A nanosecond-pulsed laser is used to join Cu/Al/Cu laminates.The laser scanning speed is used as a major parameter that affects the joint quality.First,the effect of scanning speed on weld formation is studied.The microstructural evolution of typical joints is then analyzed.Finally,the effects of welding speed on the mechanical properties are investigated,and the fracture mechanism of the joints is elucidated.Results and Discussions In terms of weld formation,the heat-affected zone at the joint edge and the penetration depth both decrease as the welding speed increases(Fig.3).The pores in the weld migrate upward as the melting depth decreases,and the joint quality improves when the welding speed is 21 mm/s(Fig.4).In terms of microstructures,the interface produces numerous bulk CuAl_(2)phases at a low welding speed(15 mm/s)(Fig.6).As the welding speed increases,the number of interfacial compounds decreases.In addition,the compound Cu_(9)Al_(4)phase appears near the copper base material,whereas the part near the aluminum is mainly subeutectic,eutectic,and perieutectic structures composed ofα-Al and CuAl_(2)phases.When the welding speed reaches 27 mm/

关 键 词：激光技术 纳秒激光焊接 Cu/Al/Cu层状复合接头 异种金属薄片 焊缝质量 

分 类 号：TG457.1[金属学及工艺—焊接]