Abstract:
In order to study the laser welding process of magnesium/aluminum dissimilar metals, the experiment was conducted on AZ31B magnesium alloy and 5083 aluminum alloy with Zn interlayer by using 4kW fiber laser. The influence mechanism of Zn interlayer on Mg/Al dissimilar metal laser welding joint was obtained. The results show that the microstructure of the weld is uniform, and the heat affected zone is not obvious. The magnesium side and the center are mainly composed of
α-Mg and
α-Mg+Mg
17Al
12 eutectic structure, and the bottom of weld is the mixture of Al, Mg/Al and Mg/Zn compounds. With the thickness of Zn increased, at the bottom of the weld, the formation of Mg/Zn compounds increase, the Mg/Al compounds reduce and the distribution of microstructure is improved. The shear fracture mode transforms from cleavage to mixed manner. When Zn interlayer is 0.1mm, the shear strength reaches the maximum 25.47MPa. The study is helpful in improving the strength of the Mg/Al dissimilar metal welded joints.