6061铝合金激光摆动-电弧复合焊组织与力学性能分析  

Study on microstructure and mechanical properties of 6061 aluminum alloy prepared by oscillating laser-arc hybrid welding

作　　者：张贺 靳军 蒋平[2] 张风东 张振鹏 周志凯 ZHANG He;JIN Jun;JIANG Ping;ZHANG Fengdong;ZHANG Zhenpeng;ZHOU Zhikai(CRRC Qingdao Sifang Co.,Ltd.,Qingdao,266111,China;Huazhong University of Science&Technology,Wuhan,430074,China;CARMAN HAAS Laser Technology(Suzhou)Co.,Ltd.,Suzhou,215000,China)

机构地区：[1]中车青岛四方机车车辆股份有限公司,青岛266111 [2]华中科技大学,武汉430074 [3]卡门哈斯激光科技(苏州)有限公司,苏州215000

出　　处：《焊接学报》2024年第1期94-102,I0008,I0009,共11页Transactions of The China Welding Institution

摘　　要：对高铁6 mm的6061铝合金进行激光摆动-电弧锁底对接焊,以焊缝熔深与气孔率为指标,借助扫描电子显微镜(scanning election microscope,SEM),电子背散射衍射(electron backscatter diffraction,EBSD)等表征手段分析了摆动频率对焊缝微观组织与力学性能的影响规律.结果表明,当摆动频率升高为250 Hz时,焊缝气孔率降至1%以下,靠近熔合线附近的焊缝区域主要由柱状枝晶组成,而焊缝中心电弧区域主要由等轴枝晶组成,激光摆动频率变化会影响单位周期内光束前进距离,进而影响光束对熔池后方的搅拌能力强弱,随着激光摆动频率的增大,熔池的搅拌作用效果增强,焊缝中心等轴枝晶细化程度明显,晶粒尺寸由68μm降至44μm.当摆动频率为250Hz时,接头的抗拉强度达到最大为229 MPa,约为母材强度的73%,焊缝气孔率的降低和焊缝中心细化的枝晶组织为接头强度提高提供了有利条件.The oscillating laser-arc welding was carried out on the 6mm thick 6061 aluminum alloy locked bottom butt joint commonly used for the roof of high-speed rail,and the effect of oscillating frequency on the microstructure and mechanical properties of the weld was systematically studied based on SEM,EBSD and other characterization methods together with the penetration and porosity of the weld as indicators.The results showed that the porosity of the joint was reduced to less than 1%when the oscillating frequency sharply increased to 250 Hz.The weld area near the fusion line was primarily arranged with columnar dendritic structures,while the central arc region of the weld was chiefly composed of equiaxed dendritic structures.Laser oscillating frequency could affect the beam advance distance in per unit cycle,which posed a significant impact on the stirring action of laser beam behind the molten pool.With the increase of the oscillating frequency,the stirring effect of the molten pool was enhanced,which effectively refined the central equiaxed structures and dropped the dendrite sizes from 68μm to 44μm.The tensile strength reached their maximum value at the oscillating frequency of 250 Hz,with a maximum tensile strength of 229 MPa,which was about 73%of that of the base metal.Both the reduction of the porosity and the refined dendrites structures of the weld largely created favorable conditions for the improved tensile strength.

关 键 词：激光摆动-电弧复合焊 摆动频率 气孔率 微观组织 力学性能 

分 类 号：TG456.7[金属学及工艺—焊接]