电脉冲处理对2024-T4铝合金搅拌摩擦焊接头性能的影响  

Effect of Electric Pulse Treatment on Properties of Friction Stir Welded Joint of 2024-T4 Aluminum Alloy

作　　者：许爱军 汤泽军[2] 章锦涛[2] 万海峰 王子涵 XU Aijun;TANG Zejun;ZHANG Jintao;WAN Haifeng;WANG Zihan(Beijing Spacecrafts Co.,Ltd.,Beijing 100090,China;College of Mechanical and Electrical Engineering,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China)

机构地区：[1]北京卫星制造厂有限公司,北京100090 [2]南京航空航天大学机电学院,南京210016

出　　处：《航空制造技术》2021年第10期64-71,共8页Aeronautical Manufacturing Technology

基　　金：先进焊接与连接国家重点实验室开放课题研究基金(AWJ-19M05)。

摘　　要：通过电脉冲对2024-T4态铝合金搅拌摩擦焊接试样进行了焊后固溶处理。结果表明,经电脉冲固溶处理后,试样强度明显降低,延伸率显著提高。当有效电流密度为135A/mm^(2)时,相比原始焊接试样,抗拉强度下降了25%,延伸率提高了50%。焊接样品的工程应力-应变曲线出现了PLC效应的锯齿状波动。随后,对135A/mm^(2)电脉冲固溶处理后的样品进行了时效处理,拉伸曲线的锯齿状波动消失,材料延伸率略微下降,强度升高,合金性能恢复到焊后水平。经人工再时效处理,试样抗拉强度比原始接头提高8%;而自然再时效处理后,抗拉强度比原始接头提高4%。微观组织显示固溶处理后,接头不同区域晶粒出现了不同程度细化。固溶过程中接头的强化相溶解,而再时效处理过程中强化相重新析出,且人工再时效处理后焊核区析出的强化相体积更大,数量更多。强化相溶解与析出是导致电脉冲固溶再时效处理后焊接试样力学性能变化及PLC效应的原因。Electrical pulse treatment was carried out on 2024-T4 aluminum alloy friction stir welding(FSW)samples.The results show that the strength of the sample decreases obviously and the elongation increases obviously after the treatment.When the effective current density is 135A/mm^(2),the tensile strength decreases by 25%and the elongation increases by 50%.The engineering stress-strain curve of the welding sample shows the zigzag fluctuation of PLC effect.After the aging treatment following by the electrical pulse treatment,the serrated fluctuation of tensile curve disappears.The elongation decreases slightly,while the strength increases.The material’s mechanical properties return to the FSW samples’level.The tensile strength of the sample is 8%higher than that of the original joint after artificial reaging treatment,while the tensile strength is 4%higher than that of the original joint after natural reaging treatment.The microstructure shows that the grains are refined to different degrees in different areas of the joint after solution-treatment.The strengthening phase dissolves in the process of solution treatment,but re-precipitates in the process of reaging treatment.In addition,the volume and quantity of strengthening phase precipitated in nugget zone after artificial reaging treatment are larger in comparison to that after natural reaging treatment.The dissolution and precipitation of strengthening phase are the reasons for the change of mechanical properties and PLC effect of FSW samples after the reaging treatment following by solution treatment.

关 键 词：2024-T4铝合金 搅拌摩擦焊 电脉冲处理 微观组织 力学性能 

分 类 号：TG453.9[金属学及工艺—焊接] V261.34[航空宇航科学与技术—航空宇航制造工程]