Research On Forming Control And Performance Of 5356 Aluminum Alloy By Arc Additive Manufacturing

Aluminum alloy thin-walled shell parts have been widely used in aviation,aerospace and other fields,but 90% of the materials are often removed during processing,which causes great waste of aluminum alloy materials and tool materials.In recent years,the development of additive manufacturing technology has provided new ideas for solving this problem.Wire Arc Additive Manufacturing(WAAM)directly shapes the near net shape of the part by layer-by-layer stacking,which has the advantages of low cost and high deposition rate,and has been an important research direction for direct forming of metal parts.This article is based on tungsten inert gas shielded welding(GTAW)technology.In the research of part forming control,the method of visually detecting and feedback controlling arc length is proposed to realize arc detection and forming control,and the arc length visual detection and feedback control module is designed.The test results show that the method can effectively control the arc length and ensure the consistency of the transition state of the deposited wire and the molten pool.Based on the construction of the additive manufacturing system,this paper combines the size of the single-layer deposition layer and the finite element temperature field simulation to study the pulse period and welding process parameters(welding peak current,welding speed,wire feed speed)affects the size of the deposited layer to determine the process window for the 5356 aluminum alloy additive manufacturing.The process experiments of thin-walled frame deposits were carried out.The pore distribution and microstructure of the thin-walled frame deposits were observed by optical microscopy.The distribution of pores and grains in the sedimentary layer was studied by image statistical method.The forming process was analyzed.The effect of the peak current ratio and the inter-layer cooling time on the pores and grains.The results show that the grain size of the thin-walled frame deposits increases layer by layer with the deposition direction;when the heat input is larger,the size and number of pores increase significantly.In terms of mechanical properties,the grain hardness of different deposition heights of thin-walled frame deposits was tested by Nano-indenter.The results show that the hardness increases as the height of the deposited layer increases.The mechanical properties of the thin-walled molded parts were tested by a tensile tester.The test results show that the tensile strength of 5356 aluminum alloy thin-walled parts manufactured by GTAW process is 230±10MPa and the elongation is about 16%.The mechanical properties are similar to those of drawn-formed homogeneous materials.The tensile fractures were observed.The results show that the fracture morphology of the thin-walled parts is a uniformly distributed dimple,which is consistent with the ductile fracture characteristics,indicating that the plasticity of the formed parts were improved.