Study on microstructure and properties of laser flux-cored wire joint of titanium alloy

The welding of TC4 titanium alloy plate was carried out by means of laser welding with filler wire and self-developed flux-cored wire, and the obtained welding joint was treated with 850 ℃ heat preservation for 2 hours and then cooled and annealed with furnace, the microstructure and mechanical properties of the welded joint were compared with those of the welded joint. The results showed that the welded joint was composed of α_p phase, α_s phase and β phase, the α' martensite structure was not found in the as-welded joint, the strength of the as-welded joint decreased, but the elongation and impact toughness at room temperature increased, and the tensile fracture of the as-welded joint was surrounded by a large number of tearing lips, the dimples are deep and uniform, showing microporous polymerized ductile fracture. It was found by XRD that the as-welded joint was mainly composed of α' martensite, and a few weak multi-angle α phase diffraction peaks were observed, and the central angle of α phase diffraction peaks in the heat-treated joint was the same as that in the as-welded joint, in addition, a rather sharp diffraction peak of β phase (110) was found.