MA Yin, HAN Xiaohui, LI Gangqing, et al.Microstructure and Properties of Laser-MIG Hybrid Welded TC4 Titanium Alloy Joints[J].Electric Welding Machine, 2023, 53(8): 93-97. DOI： 10.7512/j.issn.1001-2303.2023.08.12.
Microstructure and Properties of Laser-MIG Hybrid Welded TC4 Titanium Alloy Joints
In this paper, 3 mm thick titanium alloy was welded by laser-MIG hybrid welding technology. The microstructure, microhardness, tensile properties and corrosion resistance of the welded joints were studied. The results indicated that laser-MIG hybrid welding could realize high quality welding for TC4 titanium alloy with well weldrd formation and no obvious defects. The coarse β phase columnar crystals existed in the weld center, and the fine acicular α' martensite existed inside the crystals. The heat affected zone mainly consisted of equiaxed α phase+β phase+α' martensite, with finer grain and less martensitic α' martensite as the distance from the fusion line increased. The hardness of welded seam was the highest, followed by the heat-affected zone, and the base metal was the lowest, and the hardness of the coarse-grained zones was higher than that of the fine-grained zone in heat-affected zone. The average tensile strength of welded joints was 1 069 MPa, and the average elongation was 5.3%. The specimens fractured in the base metal close to the heat affected zone, and the fracture characteristics were plastic fracture. The corrosion resistance of the welded joints were slightly higher than that of the base metal.
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