(1. 华中科技大学 武汉光电国家实验室(筹)，武汉 430074；
2. 华中科技大学 光电子科学与工程学院，武汉 430074)
摘 要: 对8 mm厚2A12铝合金板进行CO2激光−MIG(metal inter gas)复合焊接，讨论了焊接电压和焊接速度对焊缝几何参数的影响，并研究接头显微组织和力学性能。结果表明：熔深和母材熔化面积决定于焊接速度。随着焊接电压的降低，焊缝熔宽、堆高面积、焊缝固液趾角逐渐减小，而成形系数逐渐增加。接头显微组织由α(Al)基体及α(Al)+Al2Cu+Mg2Si三相共晶组成；接头抗拉强度为281 MPa，为母材抗拉强度的69%；接头拉伸断口呈韧脆混合断裂，而母材断口呈微孔聚集型延性断裂。
关键字: 铝合金；复合焊接；焊缝几何参数；显微组织
（1. Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology,
Wuhan 430074, China
2. School of Optoelectronics Science and Engineering, Huazhong University of Science and Technology,
Wuhan 430074, China）
Abstract:The experiments of CO2 laser-metal inter gas (MIG) arc hybrid welding for 2A12 aluminum alloy with the thickness of 8 mm were carried out. The effects of arc voltage and welding speed on bead geometry parameters were discussed, and the microstructure and mechanical properties of joint were studied. The results show that the welding speed affects the bead penetration depth and bead penetration area. The bead width, bead reinforcement area and liquid-solid toe angle decrease with decreasing arc voltage, while the penetration shape factor increases with decreasing arc voltage. The microstructure of the joint is composed of α(Al) matrix and α(Al)+θ+Mg2Si eutectic. The tensile strength of the joint is 281 MPa, which is approximately 69% of base metal. The fracture surface morphology observation shows that the joint exists as brittle-ductile mixture fracture, while the base metal exists as microvoid accumulation fracture.
Key words: 2A12 aluminum alloy; hybrid welding; bead geometry parameter; microstructure
