采用双光束同步激光填丝焊接的方法制备了Ti-6Al-4V合金T型接头,使用高速摄像机拍摄了焊接过程图像并研究了热输入对焊接过程稳定性、焊缝成形、组织及力学性能的影响.试验结果表明,热输入显著影响熔池行为和填丝焊接熔滴过渡,进而影响T型接头焊缝形貌及质量.随着热输入的增加,T型接头组织发生变化,晶粒尺寸变大.热影响区及焊缝处的马氏体使得这2个区域的显微硬度高于母材.另外,沿蒙皮方向及筋条方向的抗拉伸强度随着热输入的增加而增大.由于接头处马氏体增强作用,拉伸断裂均发生于母材处.“,”The Ti-6Al-4V alloy T-joints were prepared by double-sided synchronized laser beam welding with homologous filler wires.Influence of heat input on the stability of welding process,weld formation,microstructure,and mechanical properties of Ti-6Al-4V alloy T-joints was investigated through the high-speed camera during double-sided laser beam welding process.Results show that the heat input has a significant effect on molten pool behavior and droplet transition,which influences the appearance and welded quality of the T-joints.With the increase of heat input,the morphologies of welded T-joints change and the grain size increases.Martensite forms at the heat affected zone (HAZ) and fusion zone (FZ),resulting in the fact that the microhardness of HAZ and FZ is higher than that of the skin.Moreover,the tensile strength of welded T-joints along the directions of skin and stringer increases with increasing the welding heat input.The fractures occur at the base metal part of all the specimens,which is correlated with the martensitic strengthening effect of the joints.