激光清洗改性对Kovar/CFRP搭焊接头力学性能的影响  

Effect of laser cleaning modification on mechanical properties of Kovar/CFRP lap welded joint

作　　者：胡文祥 王丹[2] 李鑫炎 张帅[2] 李洪亮 韩柯 Hu Wenxiang;Wang Dan;Li Xinyan;Zhang Shuai;Li Hongliang;Han Ke(Precitec Precise Technologies(Shanghai)Co.,Ltd.,Shanghai 201202,China;Jiangsu University,Zhenjiang 212013,Jiangsu,China)

机构地区：[1]普雷茨特精密技术(上海)有限公司,上海201202 [2]江苏大学,江苏镇江212013

出　　处：《焊接》2024年第10期8-16,共9页Welding & Joining

基　　金：国家自然科学基金资助项目(52205368);中国博士后科学基金资助项目(2023M740959)。

摘　　要：【目的】实现Kovar合金与CFRP之间的有效连接是解决航空航天器件重量问题的重要手段之一。【方法】将采用纳秒脉冲激光对Kovar合金表面进行激光改性,再利用焊接热传导工艺实现Kovar合金与CFRP之间的搭接,借助激光共聚焦、金相显微镜和扫描电子显微镜对改性材料表面,搭焊界面组织以及合金侧断口进行表征与分析,阐明其对搭焊接头剪切拉伸力的影响。【结果】当脉冲激光扫描速度较低为500 mm/s时,Kovar合金表面粗糙度最高可达14.2μm,明显高于未改性时的8.8μm;进一步增加激光扫描速度至1000 mm/s和2000 mm/s时,Kovar合金表面粗糙度分别降低到12.6μm和10.2μm。改性后合金材料表面烧蚀明显,并分布大量沟壑状烧蚀凹坑。未改性时,Kovar合金与CFRP搭焊接头平均剪切拉伸力仅为450 N左右;当激光扫描速度为500 mm/s或1000 mm/s时,接头拉伸剪切力最高可达1100 N,是未激光清洗改性时的近2.5倍;当扫描速率为2000 mm/s时,接头剪切拉伸力则有所下降,但仍明显高于未改性时的焊接接头性能。激光改性后,Kovar合金与CFRP搭焊接头剪切拉伸力明显提升。另外,断口结果也显示,Kovar合金一侧凹坑处分布有大量填充的树脂及部分碳纤维。【结论】深而宽的烧蚀凹坑,不但有助于搭焊界面CFRP侧熔融树脂的填充,还有助于碳纤维的填充,可促进接头界面形成机互锁结构,从而明显提高Kovar/CFRP搭焊接头剪切拉伸力。[Objective]The effective connection between Kovar alloy and CFRP is one of the important means to solve the weight problem of aerospace components.[Methods]In this paper,a nanosecond pulse laser was employed to modify the surface of Kovar alloy,and then welding heat conduction technology was used to achieve the overlap between Kovar alloy and CFRP.The surface of the modified material,the microstructure of the overlap welding interface,and the fracture surface of the alloy side were characterized and analyzed using a laser confocal microscopy,a metallographic microscopy and a scanning electron microscopy to elucidate effect of laser modification on the shear tensile force of the overlap welding joint.[Results]When the pulse laser scanning speed was relatively lower at 500 mm/s,the surface roughness of Kovar alloy could reach a maximum of 14.2μm,which was significantly higher than that of 8.8μm without modification.When further increasing the laser scanning speed to 1000 mm/s and 2000 mm/s,the surface roughness of Kovar alloy decreased to 12.6μm and 10.2μm,respectively.The surface of the material exhibited significant erosion after modification,and a large number of gully shaped erosion pits were distributed in the modified surface.When unmodified,the average shear tensile force of the Kovar alloy and CFRP lap welded joint was only about 450 N.When the laser scanning speed was 500 mm/s or 1000 mm/s,the maximum tensile shear force of the joint could reach 1100 N,which is nearly 2.5 times higher than that without laser cleaning modification.When the scanning rate was 2000 mm/s,the shear tensile force of the joint decreased,but it was still significantly higher than the performance of the unmodified welded joint.The shear tensile force of the Kovar alloy and CFRP lap welded joint significantly increased after laser modification.Thereby,the shear tensile strength of Kovar/CFRP overlap welding joint could be improved significantly.Moreover,the fracture results also showed that a large amount of filled resin and some

关 键 词：激光改性 搭焊接头 界面形貌 机械咬合 剪切拉伸力 

分 类 号：TG442[金属学及工艺—焊接]