A356/6082异种铝合金激光搭接接头气孔形成机理研究  

Mechanism of Pore Formation of Laser Overlapped Joint of A356/6082 Dissimilar Aluminum Alloy

作　　者：杨健 骆顺存 裴鹏飞 王晓南 宋佳 张海 Yang Jian;Luo Shuncun;Pei Pengfei;Wang Xiaonan;Song Jia;Zhang Hai(High-Performance Metal Structural Materials Research Institute,School of Iron and Steel,Soochow University,Suzhou 215021,Jiangsu,China;Weiqiao(Soochow)Lightweight Research Institute Co.,Ltd.,Suzhou 215001,Jiangsu,China)

机构地区：[1]苏州大学沙钢钢铁学院高性能金属结构材料研究院,江苏苏州215021 [2]魏桥(苏州)轻量化研究院有限公司,江苏苏州215001

出　　处：《中国激光》2024年第24期91-104,共14页Chinese Journal of Lasers

基　　金：山东省重点研发计划(2021SFGC1001);苏州市基础研究计划(SYG202324)。

摘　　要：主要研究了不同搭接工艺条件下A356/6082异种铝合金激光焊接接头气孔分布、形成机理以及气孔对搭接接头力学性能的影响。结果表明:激光搭接形式对焊缝深宽比、气孔率、气孔尺寸、气孔分布以及气泡溢出规律产生显著影响。空气入侵、Mg元素蒸发、熔池剧烈流动和匙孔不稳定是导致气孔生成的主要原因,而激光热源在深度和宽度方向上的温度差异、材料热物性差异及气泡溢出路程差异是气泡滞留在焊缝金属中的主要原因。6082/A356激光搭接接头横截面下部区域的气泡更容易滞留在熔池底部形成气孔,而中部区域的气泡倾向于移动至能量较低的搭接过渡位置附近。同时,中上部区域产生的气泡或其他溢入该位置的气泡有相对充分的时间溢出焊缝表面。激光搭接接头深宽比和气孔尺寸是决定焊接接头力学性能的重要因素。Objective With the wide application of deformed and cast aluminum alloy structural parts in automotive lightweight manufacturing,the microstructure and properties of welded joints of dissimilar aluminum alloys under various thicknesses,heat treatment states,forms of welded joints,welding methods,and welding process conditions have attracted increasing attention from scholars.However,due to the different thermal physical parameters of dissimilar aluminum alloys,the fluidity of the weld pool and the content and distribution of elements in various overlapping forms differ,leading to issues such as high porosity,segregation,and severe thermal cracking in the laser overlapped joints of A356/6082 dissimilar aluminum alloys.Therefore,this study investigates the macroscopic morphology,microstructure,and pore distribution and formation mechanism of A356/6082 welded joints with various overlapping forms in detail.Methods In this study,mechanical polishing,cleaning,and clamping are performed before welding.During the welding process,high-purity argon gas protects the upper surface of the molten pool,and the flow and keyhole behavior of the molten pool are monitored and analyzed using an Acuteye high-speed image V4.1 system.After the welding test,X-ray nondestructive testing,optical microscope(OM),and scanning electron microscope(SEM)are used to analyze the pore defects,microstructure,and precipitates in the weld.In addition,a tensile shear test of the welded joint is conducted on a universal test machine by removing the residual height of the weld surface and adding a shim at the position of the holding end of the tensile shear sample.Results and Discussions Under the same laser line energy,compared to the overlapped joint when A356 is at the upper side and 6082 is at the lower side,there is a larger area of incomplete welding on the back of the overlapped joint when A356 is at the lower side and 6082 is at the upper side,the weld depth and width are reduced,and there are larger pores in the cross section(Fig.3).When A356 i

关 键 词：异种铝合金 激光焊接 气孔 裂纹 力学性能 

分 类 号：TG457.14[金属学及工艺—焊接]