Study On 2319 Aluminum Alloy Arc Additive Manufacturing Components Microstructure And Mechanical Properties

Arc Additive Manufacturing（WAAM）is a method which welding arc is used as a heat source and welding wire used as a filling material.It plans the welding robot’s travel route through the computer,melting the welding wire into the additive manufacturing process,and finally completes the components of the 3D model.The 2319 aluminum alloy belongs to the 2 series aluminum-copper alloy which can be heat-treated and strengthened,and has the advantages of high hardness and low density,and is a well-formed material.2219 aluminum alloy is widely used in the aerospace industry.However,2219 aluminum alloy is expensive and requires high production process,and is not suitable for mass production.The 2319 aluminum alloy has almost the same composition as the 2219aluminum alloy,and is cheaper.So,it has great application value and can be mass-produced.At present,the components manufactured by additive are mainly used in aerospace,shipbuilding,automobile,medical and military industries.There are also some problems in the welding process of 2319 aluminum alloy in the welding and additive manufacturing process.Firstly,the presence of impurity elements such as Fe and Si in the wire composition may result in unfavorable properties such as Al₃Fe or Al₇Cu₂Fe,and the high temperature performance is poor.Secondly,the high porosity results in brittle fracture of the component under fatigue,which can cause serious accidents.Finally,since the additive manufacturing process is a reciprocating cycle,the temperature will increase continuously with the increase of energy,which will cause coarse grains,and may also cause segregation of components,performance is reduced.In this thesis,2319 aluminum alloy was selected as the filling material,and 5B06plate was used as the substrate,CMT welder as a heat source for the arc additive manufacturing experiment.Through metallographic observation,scanning electron microscopy and energy spectrum analysis,the microstructure of the member was mainlyα-Al,θphase（Al₂Cu）,very small amount of S（CuMgAl₂）phase,andβphase（Mg₅Al8）.And T phase（CuMg₄Al₆）,S phase is the best strengthening phase,whileβphase and T phase effect is poor.Therefore,the number of S phase,βphase and T phase can be determined by reasonable control of the Mg content in the experiment.In addition,since theθphase is relatively stable in performance,controlling the ratio of theθphase can also improve the performance of the member.In this paper,by changing the welding speed,wire feeding speed,interlayer waiting time,shielding gas flow rate,wire dry elongation and other parameters,the structure is more favorable for performance.Because the 2 series aluminum alloy is a hard aluminum alloy,the mechanical properties of the microstructure of the 2319 arc additive aluminum alloy were tested by tensile experiment and hardness experiment.Mainly reflected in the strength and hardness,but the plasticity and toughness are poor.Therefore,under the premise of improving the strength and hardness of the member,it is also necessary to improve the plasticity and toughness of the member.This thesis improves the performance of the components by controlling different additive manufacturing parameters and T4 and T6 heat treatments.