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在不同的焊接工艺参数下对8mm厚的7050-T7451铝合金板进行了搅拌摩擦焊接实验。通过对焊接接头组织的分析,发现焊核区晶粒为明显的细化再结晶等轴晶;热机影响区晶粒沿流线方向拉长且有细小沉淀相在晶界上析出;热影响区的组织发生了晶粒粗化。沿焊缝横截面的显微硬度分布呈高-低-高-低-高的趋势,硬度最低处位于后退侧的热影响区。实验结果表明,在旋转速度为375r/min、焊接速度为100mm/min时,可以获得较好的焊缝组织,抗拉强度达到了452MPa。
The friction stir welding experiment of 8mm thick 7050-T7451 aluminum alloy plate was carried out under different welding parameters. Through the analysis of the welded joint structure, it is found that the grains in the nugget nucleus are obviously refined recrystallized equiaxed grains. The grains in the heat affected zone elongate along the streamline direction and fine precipitates precipitate on the grain boundaries. The heat affected zone The organization of the grain coarsening. The distribution of microhardness along the cross section of the weld shows a trend of high-low-high-low-high, and the lowest hardness is located in the heat-affected zone on the reverse side. The experimental results show that the better weld microstructure can be obtained when the rotating speed is 375r / min and the welding speed is 100mm / min, and the tensile strength reaches 452MPa.