超声冲击作用下铝合金层片结构焊缝成形及性能  

Formation and properties of lamellar structural weld of aluminum alloy under ultrasonic impact

作　　者：陈琪昊 王程程[1] 谢志宇 毛欣宇 林三宝 CHEN Qi-hao;WANG Cheng-cheng;XIE Zhi-yu;MAO Xin-yu;LIN San-bao(School of Materials Science and Engineering,Jiangsu University of Science and Technology,Zhenjiang 212100,China;State Key Laboratory of Advanced Welding and Joining,Harbin Institute of Technology,Harbin 150001,China)

机构地区：[1]江苏科技大学材料科学与工程学院,镇江212100 [2]哈尔滨工业大学先进焊接与连接国家重点实验室,哈尔滨150001

出　　处：《中国有色金属学报》2023年第8期2441-2455,共15页The Chinese Journal of Nonferrous Metals

基　　金：国家自然科学基金资助项目(51905230);先进焊接与连接国家重点实验室开放课题研究基金资助项目(AWJ-20-M06)。

摘　　要：本文以7A04高强铝合金为焊接对象,在钨极惰性气体保护焊过程中利用超声工具头对焊缝两侧母材进行超声冲击,构建了一种类柱状晶与等轴晶交替分布的层片结构焊缝,探究了焊缝成形、微观组织及性能的变化规律。结果表明:低频机械冲击对焊接具有不利影响,焊缝熔宽和熔深减小,焊缝晶粒粗化且第二相沿冲击方向呈局部不均匀分布特征,接头强度和塑性下降。在低频机械冲击基础上耦合周期超声能量后,断后伸长率从2.57%增大到4.18%,抗拉强度从259.65 MPa增大到351.51 MPa,焊缝熔宽和熔深增大;当超声振幅为22.8μm时,焊缝晶粒细化程度最大;焊缝第二相呈细小弥散状分布,但周期超声能量作用增大了焊缝的熔合比,导致焊缝耐腐蚀性能下降。In this paper,7A04 high-strength aluminum alloy was taken as the welding object,ultrasonic horn was used to carry out ultrasonic impact on the base metal on both sides of the weld during the process of tungsten inert gas welding.A kind of lamellar structure weld with alternating distribution of columnar crystal and equiaxed crystal was constructed,and the change of weld formation,microstructure and properties was investigated.The results show that low frequency mechanical impact has adverse effects on welding.The weld width and weld depth are reduced,and the weld grain is coarsened.The second phase shows local uneven distribution along the impact direction,and the joint strength and plasticity decrease.After coupling periodic ultrasound on the basis of low-frequency mechanical impact,the elongation increases from 2.57%to 4.18%,and the tensile strength increases from 259.65 MPa to 351.51 MPa.The weld width and weld depth are increased.The weld grain is significantly refined when the ultrasonic amplitude is 22.8μm.The second phase is fine and dispersively distributed.However,the effect of periodic ultrasound increases the fusion ratio of the weld,resulting in the deterioration of the corrosion resistance of the weld.

关 键 词：7A04铝合金 电弧 随焊超声冲击 层片结构 强韧化 

分 类 号：TG444[金属学及工艺—焊接]