2519A铝合金超声辅助搅拌摩擦焊接试验分析

Experimental analysis of 2519A aluminum alloy ultrasonic assisted friction stir welding

针对2519A铝合金搅拌摩擦焊(FSW)底部虚焊和弱连接等问题,通过搅拌头施加纵深超声能,形成超声辅助搅拌摩擦焊(UAFSW),进行了同种工艺条件下的FSW与UAFSW对比试验分析.结果表明,超声能的加入,使焊接区金属的塑性变形阻力降低,UAFSW焊缝整体流变区域明显增大加深,且超声能贯穿到焊缝底部,使底部流动性增强,降低了缺陷率,使焊核区连续动态再结晶过程获得的晶粒尺寸更细小,且析出的第二相更精细;UAFSW焊缝的抗拉强度达到364.62 MPa,为母材抗拉强度的79.25%,比FSW焊缝提高4.10%,平均屈服强度则显著提高10.98%,但断后伸长率有所降低.

To reduce and weak connectivity and defects of bottom weld in the friction stir welding of 2519 A aluminum alloy,comparative tests of aluminum alloy 2519 A by using UAFSW and FSW were performed. The results showed that the addition of ultrasonic energy reduced the plastic deformation resistance of the weld zone,and made the overall rheological area significantly increase in UAFSW weld. And the penetration of ultrasound to the bottom of the weld enhanced liquidity and reduced the defect rate. The grain size obtained by the continuous dynamic recrystallization process was smaller and the second phase was finer.Tensile strength of UAFSW weld is 364. 62 MPa and 79. 25% for the base metal tensile strength,which is 4. 10% higher than that of FSW weld,and the average yield strength is increased by10. 98%,but the elongation is decreased.