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The internal quality,microstructure and mechanical properties of the welded joint by TIG welding of Ti-AlFe low cost titanium alloy are studied,and are compared with TC4 titanium alloy. The results show that the surface quality,the internal fusion and the weld-ability of the Ti-Al-Fe low cost titanium alloy weld is better,and there is no welding defect. The macrostructure of the weld zone is coarse columnar crystal and a small amount of equiaxed crystal,and the columnar crystal structure of Ti-Al-Fe low cost titanium alloy is finer. The microstructure is composed of acicular secondary α phase and a small amount of elongated primary α phase,and the acicular secondary α phase of TC4 titanium alloy is finer. The heat affected zone( HAZ) is coarse equiaxed crystal,and the microstructure is consists of a large number of primary α phase,a small amount of acicular secondary α phase and residual β phase.The tensile strength of Ti-Al-Fe low cost titanium alloy weld reaches 1 204 MPa,which is 111 MPa higher than that of TC4 titanium alloy.