Study On Wire And Arc Additive Manufacturing Forming Process Of TC4 Titanium Alloy

The wire and arc additive manufacturing use the arc as the heat source which melt the synchronous welding wire to form droplets,with the deposition process droplet continuously falling into the molten pool eventually forming the deposition layer.Compared with other additive manufacturing technologies,this technology has many advantages,such as high utilization rate of materials,high manufacturing efficiency,rapid manufacturing of large metal complex structure parts and so on.It has broad application prospects in aerospace,aviation,shipbuilding and other fields.In this paper,the forming process of the wire and arc additive manufacturing is studied.Firstly,the arc forming process parameters of TC4 titanium alloy is optimized in order to obtain the appropriate parameters combination.The results show that the parameters of arc forming process suitable for TC4 titanium alloy are as follows,the welding voltage 25.0V,the wire feed speed 7.0m/min,the welding speed 15.0mm/s,the scanning distance 3.5mm and the layer height 2.0mm.Additionally,the microstructure of as-deposited and annealed sample under the wire and arc additive manufacturing and the laser deposition manufacturing is comparative studied.The differences of mechanical properties of the two kinds of specimens is analyzed in detail.The experimental result show that the microstructure of specimens is fine basketweave.After the heat treatment,the microstructure of WAAM specimen become to coarse lamellar basketweave,the alpha phase in the microstructure of LDAM specimen present a short-bar morphology;the alpha phase length-width ratio all decrease.Annealing treatment can make the strength slightly decrease and the plasticity improve obviously in the specimen,the strength of the deposited and annealed states between two kinds of specimens have little difference,but the plasticity of the WAAM specimen is lower than the LDAM specimen.Finally,the effects of different heat treatment systems and sampling directions on the microstructure and tensile properties.The results show that the size and content of ? phase will change with the increase of annealing temperature,resulting in changes in the microhardness of the sample.After annealing at different temperature,the tensile strength of the samples decreases as a whole,while the plasticity is improved.In addition,there is anisotropy in the mechanical properties of the arc additive TC4 titanium alloy.