Study on microstructure and properties of titanium alloy wall fabricated by laser-TIG arc

Using TC4 titanium alloy welding wire as raw material, through laser-TIG arc hybrid heat source wire additive manufacturing technology, combined with reciprocating scanning method for deposition, the effects of different process parameters on the tensile properties, impact properties and hardness of additive specimens were studied. The results show that: (1) With the increase of laser power, the average layer width of the formed part increases from 7.1 mm to 12.1 mm, an increase of 59%; the average layer height decreased from 1.95 mm to 1.56 mm, a decrease of 20%. (2) When the laser power is 1100 W, the transverse tensile strength is 896 MPa, the longitudinal tensile strength is 883 MPa, and the difference between transverse and longitudinal tensile strength is 13 MPa. The elongation after transverse fracture is 9.31%, the elongation after longitudinal fracture is 10.23%, and the difference of elongation after transverse and longitudinal fracture is 0.92%. (3) The impact energy of the additive samples at room temperature (25°C) in two directions is 48.5 J·cm-² (X direction) and 52.2K J·cm-² (Y direction), respectively, and the microhardness of the top of the wall is higher than that of the middle end of the wall. This study provides an important experimental basis for the engineering application of laser-TIG arc additive manufacturing technology of TC4 titanium alloy.