Study On CMT Arc Additive Manufacturing Technology And Microstructure And Properties For 5556 Aluminum Alloy

Additive manufacturing is a technology that combines computers and materials science to create entities by stacking them layer by layer.The additive manufacturing technology of aluminum alloy has the advantages of being able to produce aluminum alloy parts of various shapes,high forming efficiency and low cost.It is commonly used in aviation,shipbuilding and it is relatively widely used in conventional industries.ER5556 aluminum alloy welding wire is one of the 5th series existing welding wires with higher strength.It has excellent mechanical properties and corrosion resistance,so it is especially suitable for additive printing.At present,there are few research reports on 5556 aluminum alloy cold metal transfer welding arc additive manufacturing technology at home and abroad.In this paper,the additive manufacturing equipment with CMT arc as the heat source is used to carry out additive experiments with ER5556 aluminum alloy welding wire with a diameter of 1.2mm.Based on the single-layer single-pass process,the focus is on the forming characteristics,microstructures and properties of multilayer single-pass additive parts.Orthogonal test is designed to determine the optimal process parameters,and the 5556 aluminum alloy arc additive process is numerically simulated and analyzed.The results show that with the increase of welding current and interlayer residence time and the decrease of welding speed,the forming size of multilayer single-pass additive increases.Reducing the welding current and increasing the welding speed can make the microstructures and grain of the multilayer single-pass additive part finer and more evenly distributed.Increasing the gas flow is conducive to uniform microstructures,and reducing the residence time between layers will result in the formation of coarse grains.The maximum transverse tensile strength of the multilayer single-pass additive is 382.1MPa,and the average impact absorption energy at room temperature is about 26 J.Those are all better than ER5556 welding wire.Both tensilefractures and impact fractures are plastic fracture.The average microhardness value is about 125 HV.The corrosion resistance of 5556 aluminum alloy additive parts is good.The penetration depth of the additive part obtained by simulation is in good agreement with the penetration depth measured by metallography and the simulated temperature field is in good agreement with the actual measured temperature.It proves that the established heat source model is accurate and the numerical simulation results are reliable.It can be used to determine the additive process parameters,better control the additive process,and is conducive to obtaining additive samples with excellent forming and performance.This experiment takes the highest transverse tensile strength as the standard,and the optimal process parameters are obtained as follows: welding current is 90 A,welding speed is 700mm/min,gas flow rate is 22.5L/min and interlayer residence time is 5min.