The tensile properties of 2219 aluminum alloy plate butt joint welded by novel laser mirror welding

Abstract

For thicker weldments, penetration requires higher welding heat input. The significant difference in temperature between the front and back of the weldment will inevitably produce more significant welding distortion. The symmetrical double laser heat sources act on the flat plate butt joint structure during the laser mirror welding process, which can realize the deformation-free and high-efficiency welding of thick plates. Due to the particular welding method of laser mirror welding, there are complex interactions of double keyholes and double-sided joint pools during the welding process. However, there is no relevant research on laser mirror welding of aluminum alloys. Therefore, experimental analysis on laser mirror welding of the 2219 aluminum alloy is performed in this paper. The relationship between welding process parameters and weld bead formation is explored by quantitative research about the macro morphology of the weld seam. Then, the typical microstructure distribution is studied by the microstructure of laser mirror welded joints. Finally, the tensile test experiment is performed to observe the microscopic morphology of the tensile fracture to analyze the fracture mode of the joint. This article discussed the intrinsic relationship between the stability of the molten pool and the tensile properties. The study found that when the molten pool is formed, the stability of the keyhole is the worst, and the tensile performance is poor.