Microstructure and properties of 6061 aluminum alloy by MIG wire and arc additive manufacturing

The deposition formability of MIG wire and arc additive manufacturing of 6061 aluminum alloy components is investigated, and the microstructure and mechanical properties of different areas of the deposited parts are studied. The results show that: when the ratio of wire feeding speed/welding speed(F/T) is between 0.5 and 1, meanwhile the wire feeding speed is between 5 and 7 m/min, a good weld bead morphology can be obtained; the interfaces between layers are the bonding layers, and the rest regions are the deposition layer. The bonding layer and the deposition layer show a morphology of alternating gray and white bands along the stack height direction, bonding layers are easier to produce the pore defect; micro hardness and tensile tests show that the hardness changes little along the deposition direction, the hardness of the bonding layer is lower than that of the deposition layer, besides the hardness fluctuation is greater; there is little difference in the strength and plasticity of the horizontal direction in different regions. ; The strength is slightly higher in the deposition direction than the horizontal direction, and the elongation after fracture is 5.6% and 3.4% respectively. The tensile fractures in both directions are mainly dimples, which indicates ductile fractures.