MIG电弧增材制造6061铝合金的组织和性能

探索MIG电弧增材制造6061铝合金构件的工艺成形性，并对成形件不同区域的微观组织及力学性能开展研究.结果表明,当送丝速度/焊接速度的比值P在0.5 ~ 1之间,且送丝速度在5 ~ 7 m/min之间时，可获得良好焊道形貌；堆积焊道层与层之间交界处为结合层，其余区域为沉积层，结合层和沉积层呈现出沿堆积高度方向灰白色带依次交替的形貌，并都呈现出各种尺寸大小的气孔多发的状态；显微硬度和拉伸测试发现:沿着堆积方向硬度变化不大，结合层硬度低于沉积层，且硬度波动性更大；不同区域水平方向强度差异不大，堆积方向强度比水平方向略低，平均断后伸长率分别为18%和22.6%，两个方向拉伸断口皆以韧窝为主，属于韧性断裂.

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.