Microstructure and mechanical properties of CuCrZr /Inconel 625 laser welding joints on HEPS storage ring vacuum box

In this paper, the laser butt welding experiment of CuCrZr and Inconel 625 dissimilar material alloy tube was carried out, and the joint morphology, microstructure, chemical composition and mechanical properties of each sample were observed and analyzed. The experimental results show that the weld is in good shape under the laser power of 1100 W − 1300 W, the defocus amount of + 20 mm and the welding speed of 14.5 mm/s, and the weld is in good shape when shielded by 99.9%Ar gas of 20 L/min. The all-position welding of Inconel 625/CuCrZr pipe can be realized, and the internal defects of the weld are less. However, the phenomenon of weld collapse is obvious with the increase of welding power. The transition of interface elements between Inconel 625/CuCrZr weld and base metal is obvious. Due to the mutual solubility of Ni and Cu, there is mainly Ni-rich Ni/Cu solid solution inside the weld. In the process of laser welding, copper base metal is stirred by laser, and some copper base metal is “involved” in the weld, which remains in the weld after the workpiece is cooled. The tensile strength of laser welded joint of Inconel 625/CuCrZr pipe is high, the main fracture position is the position of HAZ of coarse-grained CuCrZr, and the fracture form is mainly ductile fracture of CuCrZr base metal.