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针对飞机蒙皮对接时,因搅拌摩擦焊(FSW)工艺窗口狭窄易致底部虚焊、弱连接等缺陷问题,为了探索更适合大飞机蒙皮长程稳定焊接的新方法,设计了超声辅助搅拌摩擦焊(UAFSW)与FSW的蒙皮连接对比试验,采用1.8 mm厚度的2524-T3铝合金进行了同种工艺条件下的UAFSW与FSW焊接,对表面成形良好、内部无缺陷的FSW与UAFSW焊缝,进行了拉伸、金相、扫描电镜观察等对比分析试验。结果表明,与FSW焊缝相比,UAFSW焊缝缺陷率明显降低,工艺窗口扩大;UAFSW焊缝表面纹理更细密,层叠现象消失;UAFSW焊缝的平均抗拉强度略高于FSW焊缝,达到母材强度的90.7%;UAFSW焊缝的平均延伸率则比FSW焊缝高20%左右。研究发现,超声的加入使UAFSW焊缝微观组织更细更均匀,晶粒尺寸变细小,且晶粒沿轧制方向的规律性被打乱,呈现无明显方向的杂序排列。
In order to explore the new method which is more suitable for long-range and stable welding of large aircraft skin, the ultrasonic assisted friction stir friction (FSW) friction stir welding Welding (UAFSW) and FSW skin connection comparison test, the UAFSW and FSW welding under the same process conditions using 1.8 mm thick 2524-T3 aluminum alloy, the surface is formed well, the internal defect-free FSW and UAFSW weld , Carried out tensile, metallographic, scanning electron microscopy and other comparative analysis test. The results show that compared with the FSW weld, the defect rate of the UAFSW weld decreases obviously and the process window enlarges. The surface texture of the UAFSW weld is finer and the lamination phenomenon disappears. The average tensile strength of the UAFSW weld is slightly higher than that of the FSW weld, 90.7% strength of the base metal; UAFSW average elongation of the weld is about 20% higher than the FSW weld. The results show that the microstructure of the weld of UAFSW is finer and more uniform, the grain size is smaller and the regularity of the grains along the rolling direction is disrupted, and there is no misordered arrangement.