Effect of different filler wires on weld formation for fiber laser welding 6A02 Aluminum alloy

[摘要] 6A02 aluminum alloy was welded by fibre laser welding with two different filler wires (ER4043 and ER5356). The weld apperance, microstructure and mechanical properties were analysed. The results show the welding course with ER4043 is more stable than that with ER5356, and the welding spatters of the former are smaller than that of the latter. The microsturtrue of the weld zone, including columnar-grains near the fusion zone and mixed microstructures (columnar grains and equiaxed grains) in the weld center zone, is finer with ER5356 than that with ER4043. So the average microhardness value of the former is higher than the latter. A great number of low melting point eutectic phases disperse in grains boundary. Due to the eutectic phases distributing more in two zones (overheat zone near the fusion zone and the weld center zone) than other zones, the welded joints have these two low hardness and weak strength zones. The ultimate strength and the elongations after fracture of the welded joints with ER4043 are lower than that with ER5356 slihgtly. However, the former are improved obviously and higher than the latter after heat treatment. The tensile properties of all joints can reach to the base material level. And the tensile fractures always occur near the fusion zone.

[发布机构] Science and Technology on Power Beam Processes Laboratory, Beijing Aeronautical Manufacturing Technology Research Institute, Beijing; 100024, China^1

[效力级别] 机械制造 [学科分类] 材料科学（综合）

[关键词] After-heat treatment;Equi-axed grains;Low melting point;Microstructure and mechanical properties;Mixed microstructures;Tensile fractures;Ultimate strength;Welding spatter