填充焊丝对6A02铝合金光纤激光焊接接头组织性能的影响

采用ER4043焊丝开展了1.0 mm厚6A02铝合金的光纤激光填丝焊接，对比分析了是否填丝对焊缝横截面形貌、接头组织、显微硬度分布和拉伸性能的影响.结果表明，激光填丝焊缝成形饱满，能够显著提高焊前装配的最大间隙容忍裕度.与自熔激光焊接接头相比，激光填丝焊接接头熔合区附近的柱状晶组织和焊缝中心的混合组织（柱状晶+等轴晶）均相对粗化，接头软化现象更加明显，焊态时接头抗拉强度基本相当，仅达到母材水平的83.2%，但经历固溶时效热处理后，接头强度得以恢复，并高于母材水平，断后伸长率获得显著改善，可以达到21.29%，远高于前者的8.13%.

Effects of filler wire on microstructure and mechanical properties for fiber laser welding 6A02 aluminum alloy

6A02 aluminum alloy with 1.0 mm thickness was welded by fiber laser beam. And the ER4043 filler wire was also used during the welding course. The effects of filler wire on cross-section of welds and characteristics of joints (including microstructure, microhardness and tensile properties) were analyzed. The results show that the welded seam by laser welding with filler wire (LWFW) is very full. It also could increase the maximum assembly gap tolerance obviously. The microstructures of joint by LWFW, either the columnar structures near the fusion zone or the mixed microstructures (including columnar grains and equiaxed grains) in the weld center zone, are coarser than that by autogenous laser welding. The softening phenomenon of the former is more serious than that of the latter. The tensile strength in welded state of the former is basically equal to that of the latter, which could reach to 83.2% of the base metal level. However, the strength could be recovered by solution and ageing heat treatment, and higher than the base metal level. The joint elongation by LWFW is improved obviously and reaches to 21.29%, which is larger than 8.13% of that by autogenous laser welding.