激光功率对高强Al-Mg-Si-Cu合金激光-CMT复合焊接接头组织性能的影响  

Effect of Laser Power on Microstructure and Properties of High Strength Al-Mg-Si-Cu Alloy Laser-CMT Hybrid Welded Joints

作　　者：张禄中 王晓南 陈夏明 陈文刚[1] 李响[4] 长海博文 Zhang Luzhong;Wang Xiaonan;Chen Xiaming;Chen Wengang;Li Xiang;Nagaumi Hiromi(School of Machinery and Transportation,Southwest Forestry University,Kunming 650224,Yunan,China;School of Iron and Steel,Soochow University,Suzhou 215021,Jiangsu,China;HighPerformance Metal Structural Materials Research Institute,Soochow University,Suzhou 215021,Jiangsu,China;Wuxi Raycus Fiber Laser Technology Co.,Ltd.,Wuxi 214174,Jiangsu,China)

机构地区：[1]西南林业大学机械与交通学院,云南昆明650224 [2]苏州大学沙钢钢铁学院,江苏苏州215021 [3]苏州大学高性能金属结构材料研究院,江苏苏州215021 [4]无锡锐科光纤激光技术有限责任公司,江苏无锡214174

出　　处：《中国激光》2023年第4期129-137,共9页Chinese Journal of Lasers

基　　金：国家自然科学基金联合项目(U1864209);国家自然科学基金(51865053);江苏省“青蓝工程”计划项目。

摘　　要：采用激光-CMT复合焊接工艺(CMT,冷金属过渡)对2 mm厚400 MPa级Al-Mg-Si-Cu合金进行焊接,研究了激光功率对焊接接头宏观形貌及组织性能的影响。研究表明:激光功率达到3.6 kW时可获得全熔透焊接接头,随着激光功率的增加,熔宽不断增加而焊缝余高有所降低。熔宽增加和余高降低使得焊缝稀释率增加,焊缝中硅元素含量降低。随着激光功率的增加,焊缝中烧损的镁元素增加,镁元素含量亦有所降低。焊缝中镁和硅元素含量的降低导致固溶强化效果减弱。随着激光功率的增加,全熔透焊缝的硬度逐渐降低。密集气孔的存在进一步恶化了焊缝性能,导致拉伸过程中焊缝处的断裂。焊接接头抗拉强度亦呈不断降低的趋势,在激光功率为3.6 kW时,焊接接头的平均硬度和抗拉强度分别达到基材的65%(85 HV)和64%(271 MPa)。Objectives As a heat-treatable high-strength aluminum alloy with low density,good mechanical properties,easy forming,and corrosion resistance,Al-Mg-Si alloys have been widely used in high-speed railroads,automobiles,aerospace,and other fields.The addition of Cu to Al-Mg-Si alloys is more economical and applicable.It improves the mechanical properties and age-hardening efficiency at peak aging,resulting in ultimate tensile strength of 400 MPa at peak aging for high-strength Al-Mg-Si-Cu alloys,which is significantly higher than that of existing commercial Al-Mg-Si alloys.Softening the heat-affected zone during welding is a major problem that limits the use of heat-treatable aluminum alloys.Laser-CMT composite welding(CMT,cold metal transfer)is a promising high-performance,low-welding distortion technology that utilizes the advantages of laser and CMT welding to overcome the shortcomings of both singlelaser and traditional arc welding,while increasing productivity and improving welding quality.Therefore,this study investigates the effects of laser power on the macroscopic morphology and tissue properties of the welded joints of highstrength Al-Mg-Si-Cu alloys and evaluates the possibility of applying laser-CMT composite welding technology to highstrength Al-Mg-Si-Cu alloys.Methods In this study,a high strength Al-Mg-Si-Cu alloy with a thickness of 2 mm and filler wire with a diameter of1.2 mm were used.A 6-kW laser and arc welding machine were used for butt-welding laser-CMT hybrid welding experiments.The welding parameters were as follows:laser powers of 3.0,3.6,4.2,and 4.8 kW;wire-feeding speed of4 m/min;welding speed of 4 m/min;laser beam diameter of 0.3 mm,and the distance of 3 mm between the laser beam and arc.The specimens were then etched using the Keller reagent(1 mL HF,1.5 mL HCl,2.5 mL HNO3,and 95 mL H2O).The microstructures of the fusion zone and bead dimensions for every welding condition were examined using an optical microscope(OM).The weld microstructure was analyzed using scanning electron microscopy

关 键 词：激光技术 高强Al-Mg-Si-Cu合金 激光-CMT复合焊接 显微组织 力学性能 

分 类 号：TG457.14[金属学及工艺—焊接]