TC4ELI钛合金真空激光横焊接头组织及性能研究OA

In order to solve the problem of controlling heat input,and uniform joint properties and the limitations of conventional welding processes in thick-plate titanium alloy welding,a single-pass full-penetration welding test is done at the horizontal welding site on 50 mm thick TC4ELI titanium alloy by using vacuum laser beam welding.A single-pass full-penetration forming of titanium alloy at the horizontal welding site was successfully achieved;the microstructure and the properties of the weld have been studied.The results indicate that the weld bead exhibits continuous and uniform formation on both the top and bottom surfaces,with a top width of approximately 3.8 mm and a root width of about 2.9 mm.The weld was free from defects such as pores,cracks,and lack of fusion.The X-ray inspection results comply with the Class Ⅰ requirements of standard NB/T 47013.2-2015.The joint microstructure displays distinct zonal characteristics:the fusion zone consists primarily of acicular α phase,α'martensite,and intergranular β phase,with the high-aspect-ratio acicular α phase aligned parallel to form clusters.The heat-affected zone(HAZ)is characterized by primary α phase,acicular α phase,and lamellar α phase.The width of the HAZ was controlled within the range of 0.8～1.0 mm,with no significant grain coarsening observed.The average tensile strength,yield strength,and elongation were 900 MPa,799 MPa,and 14.5％,respectively,equivalent to 101％,103.6％,and 81.4％of the base metal(BM)properties.Fracture consistently occurred in the base metal.The impact absorbed energy of the fusion zone ranged from 27.3 J to 30 J,approximately 67.1％～77.5％of that of the base metal.This research demonstrates the feasibility of vacuum laser horizontal welding for high-quality joining of thick-plate titanium alloys,providing crucial process support and a theoretical basis for the welding manufacturing of large titanium alloy structures in deep-sea,aerospace,and other demanding applications.