Abstract:The microstructures?and properties of TC4 titanium alloy?prepared via?TIG arc additive manufacturing?were studied.?The results show that the microstructure of the arc additive?manufacturing?TC4 titanium alloy is different from the as-cast characteristics of the arc additive?manufacturing?steel material, which has significant heat-treated characteristics. It is a basketweave?structure composed of α and β phases.?Analyzing the formation process, it can be found that the primary structure of the additive body is dendrites, which has obvious orientation at this time; with the action of multiple reheating in the subsequent additive process, since the low thermal conductivity of titanium, the additive body maintains a higher?temperature, the dendrite composition gradually becomes uniform and transforms into anisotropic slender β crystal grains; then the temperature decreases and transforms into a two-phase basketweave?structure of α and β, and the α phase is in a supersaturated state, the β-phase precipitated?with nano-scale dots?can be observed,?the structure and performance is close to isotropic at this time,?the tensile strength?and the elongation after fracture at room temperature can reach up to 998 MPa?and?8.7%, respectively.