C24S新型铝锂合金焊接工艺研究  

Study on Welding Processes of C24S New Type Al-Li Alloy

作　　者：季勇志 JI Yongzhi(College of Mechanical and Electrical Engineering,Binzhou University,Binzhou 256600,China)

机构地区：[1]滨州学院机电工程学院,山东滨州256600

出　　处：《热加工工艺》2020年第7期44-47,52,共5页Hot Working Technology

基　　金：2017年度校级博士科研启动项目(2017Y21);2019年国家教育部产学合作协同育人项目(2019-2020)。

摘　　要：对2 mm C24S铝锂合金薄板进行了GTAW和LBW机器人焊接工艺试验,采用光学显微镜(OM)和扫描电镜(SEM)分析了两种方法下接头显微组织,并测试了接头的力学性能。结果表明:GTAW所得接头出现气孔缺陷,焊缝和热影响区组织粗大。焊缝由粗大的胞状晶组成,析出物呈条带状沿晶界分布,抗拉强度仅为母材的60.3%。LBW焊接头成形良好,焊缝由尺寸一致的细小等轴晶组成,且焊缝中弥散分布着大量细小的颗粒状析出物。LBW焊焊缝在各区域沿熔深方向组织分布存在差异,靠近热影响区形成了细晶区,细晶区的宽度以及焊缝中心的显微组织与焊接时熔池金属流动行为密切相关。LBW焊接头呈现出高强度、高伸长率和高硬度的综合力学性能,抗拉强度达到347.8 MPa,为母材的79.1%,焊缝硬度高达105.4 HV,且拉伸断口中分布着细小、尺寸均匀的韧窝。The GTAW and LBW welding process tests of 2 mm thick C24S Al-Li plates were carried out. The microstructure of welding joints by these two welding methods was analyzed by optical microscopy and scanning electron microscopy, and the mechanical properties of these joints were also tested. The results show that pore defect in the welded joint by GTAW occurs, the microstructure of the weld seam and HAZ in GTAW joint is coarse. The microstructure of weld seam consists of cellular crystals. The precipitates are distributed along the grain boundary in strip shape. The tensile strength of joint is only 60.3% of the base metal. The LBW joint has good formation and the microstructure of weld seam is composed of equiaxed grains with the same size, and a large number of fine particles are distributed in it. Meanwhile, the microstructure of the LBW weld is different in different zones along penetration direction, the fine grain zone forms near HAZ, and the width of fine grain zone and microstructure of weld center is closely related to the metal flow behavior in weld pool. The joint of LBW shows good comprehensive mechanical properties with high strength, high elongation and high hardness. The tensile strength of LBW welding joint is 347.8 MPa, which is 79.1% of the base metal. The average microhardness of the weld is 105.4 HV and the fracture is consisted of small dimples with uniform sizes.

关 键 词：C24S铝锂合金 GTAW焊 LBW焊 等轴晶 力学性能 

分 类 号：TG457.14[金属学及工艺—焊接]