7B52铝合金激光-MIG复合焊接头组织与性能

Microstructure and properties of 7B52 aluminum alloy joint welded by laser-MIG hybrid welding

用激光-MIG复合焊接7B52叠层铝合金板材,对接头显微组织、硬度、拉伸力学性能等进行分析。结果表明:复合焊接头由于激光和电弧热源特性不同,导致接头电弧区与激光区组织、性能存在显著差异;电弧区与激光区焊缝内部组织为等轴晶,激光区平均晶粒尺寸为7.4μm,明显小于电弧区平均晶粒尺寸13.6μm;电弧区平均硬度为85HV,低于激光区平均硬度108HV,复合焊的热影响区宽度小于单一MIG焊接;复合焊接头的平均抗拉强度为356 MPa,断裂机制为韧脆复合型断裂。

Welding of 7B52 laminated aluminum alloy plate was carried out using laser-MIG hybrid welding,and the microstructure,hardness,and tensile properties of joint were analyzed. The results show that due to the different characteristics of heat source of laser and arc,the structure and performance of the arc zone and laser zone in joints are significantly different.The internal microstructure of the weld in the arc zone and the laser zone is mainly equiaxed grain,and the average grain size of the laser zone is 7.4 μm,which is significantly smaller than the average grain size of the arc zone of 13.6 μm. The average hardness of the arc zone of 85 HV is lower than that of the laser zone of 108 HV. The width of the heat-affected zone of hybrid welded joint is smaller than that of the single MIG welded joint. The average tensile strength of hybrid welded joint is 356 MPa.The fracture mechanism is a combination of ductile fracture and brittle fracture.