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以铝锂合金2A97(底板)/2099(筋板)T型接头为研究对象,采用ER5356铝镁焊丝进行激光填丝焊接,分析了焊接接头的显微组织和力学性能。结果表明:接头的平均抗拉强度为425 MPa,达到2A97-T3母材抗拉强度的93%。T型接头首先在焊趾起裂,然后沿熔合线扩展,最终断在底板,呈穿晶断裂的特征。焊缝区硬度值在70~90 HV之间,比母材硬度低。焊缝区域晶粒形态主要有细等轴晶、柱状晶和等轴晶,其中细等轴晶主要在在熔合区靠近焊缝侧形成;焊缝中心等轴晶区的第二相粒子分别在晶间和晶内出现,并伴随明显的铜偏析现象。
Taking aluminum-lithium alloy 2A97 (bottom plate) / 2099 (rib) T-joint as the research object, ER5356 aluminum-magnesium welding wire was used for laser welding, and the microstructure and mechanical properties of the welded joint were analyzed. The results show that the average tensile strength of the joint is 425 MPa, reaching 93% of the tensile strength of 2A97-T3 base metal. T-joints first in the weld toe crack, and then extended along the fuse line, and finally broken in the floor, was transgranular fracture characteristics. Weld zone hardness value between 70 ~ 90 HV, lower than the base metal hardness. The grain morphology in the weld zone mainly includes fine equiaxed grains, columnar grains and equiaxed grains. The fine equiaxed grains are mainly formed near the weld side in the fusion zone. The second phase grains in equiaxed zone of the weld center are in Intergranular and intragranular, and accompanied by significant copper segregation phenomenon.