Characterization of laser arc hybrid welding process for medium-thick titanium alloy plate

Laser-CMT welding method was used to achieve one-side welding with back formation without beveling for 10 mm thick titanium alloy. The microstructure, mechanical properties and corrosion performance of the weld are tested and analyzed. The experimental results show that the welded joint formed under the optimal parameters is mainly composed of a large amount of α' martensite and incipient α term, and there is a net basket organization, the microhardness of the welded area is up to 380 HV, greater than the parent material area, and due to a faster cooling rate of the laser zone, more α' martensite generated at the bottom of the weld. The tensile strength of the welded joint can reach 916 MPa, the fracture elongation reaches 16.08%, tthe tensile fracture exhibits typical ductile fracture characteristics, and the microstructural properties in the seam are significantly better than in the base material area. The corrosion resistance of the seam is better than that of the base material because of the finer grains and large number of dislocations in the microstructure, which enhance the passivation ability and hinder the diffusion of Cl⁻.