热输入对7075-T6超高强铝合金激光填丝焊焊缝组织与力学性能的影响  

The effect of heat input on the microstructure and mechanical properties of 7075-T6 ultra-high strength aluminum alloy weld by laser wire filling welding

作　　者：高文强 许飞 马旭颐 郭路云 鲁奕廷 GAO Wenqiang;XU Fei;MA Xuyi;GUO Luyun;LU Yiting(Key Laboratory of High-Power Beam Processing Technology,AVIC Manufacturing Technology Institute,Beijing,100024,China)

机构地区：[1]中国航空制造技术研究院,高能束流加工技术重点实验室,北京100024

出　　处：《焊接学报》2025年第1期128-136,共9页Transactions of The China Welding Institution

基　　金：国家重点研发计划项目(2023YFB4606200)。

摘　　要：利用激光填丝焊实现了厚度为2.0 mm的7075-T6超高强铝合金的高质量连接,并研究了热输入对超高强铝合金焊缝组织与力学性能的影响.7075-T6铝合金激光填丝焊焊缝组织为典型的铸态组织.焊缝中心区为无明显织构、尺寸较大的等轴晶组织,且焊缝中强化相颗粒无法充分析出,导致接头强度出现一定程度的下降.随着热输入的增加,焊缝横截面的熔凝区面积以及熔宽逐渐增加,而焊缝中心处等轴枝晶的组织和织构特征均未发生显著变化,晶粒尺寸呈现先快速增大后缓慢增加的趋势.不同热输入条件下焊接接头的显微硬度分布趋势基本相同,接头软化最严重的区域均在焊缝.随着热输入的增加,焊接接头的抗拉强度呈现先增加后下降的趋势.通过对激光填丝焊热输入的调控,能够使7075铝合金焊接接头的强度系数达到74.9%.High quality connection of 2.0 mm thick 7075-T6 ultra-high strength aluminum alloy was achieved using laser wire filling welding,and the effect of heat input on the microstructure and mechanical properties of ultra-high strength aluminum alloy welds was studied.The microstructure of the 7075-T6 aluminum alloy weld by laser wire filling welding was a typical cast structure.The central area of the weld was a relatively large equiaxed dendritic structure with no obvious texture,and the strengthening phase particles in the weld could not be fully precipitated,resulting in a certain degree of decrease in joint strength.With the increase of heat input,the melting zone and melting width of the weld cross-section gradually increased,while the microstructure and texture characteristics of equiaxed dendrites at the center of the weld did not show significant changes.The grain size of the central area of the weld first rapidly increased and then slowly increased.The microhardness distribution of joints under different heat input conditions was basically the same,and the areas with the most severe softening were all in the weld zone.With the increase of heat input,the tensile strength of joints firstly increased and then decreased.By regulating the heat input of laser wire filling welding,the strength coefficient of 7075 aluminum alloy joints could reach 74.9%.

关 键 词：热输入 7075铝合金 激光填丝焊 焊缝组织 力学性能 

分 类 号：TG456.7[金属学及工艺—焊接]