20mm厚6063铝合金搅拌摩擦焊焊缝S曲线控制

Elimination of lazy S defect in friction stir welded joint of 20mm-6063 alumimum alloy

摘要: 针对6063铝合金搅拌摩擦焊缝中易出现"S"曲线的问题,在采用搅拌摩擦焊焊接20 mm厚6063铝合金散热器的过程中,使用气体保护,成功消除了6063铝合金搅拌摩擦焊中易形成的"S"曲线,获得了成形良好的焊缝组织,焊缝的平均抗拉强度达到148.83 MPa,焊接强度系数为母材的81.9%.通过分析焊缝的微观组织,发现焊核区发生了完全动态再结晶,组织为细小的等轴晶粒.热力影响区发生明显塑性变形,发生不同程度的动态再结晶,晶粒发生明显长大.热影响区受焊接热循环影响,发生了微观组织和力学性能变化,但没有发生塑性变形,晶粒发生粗化.

Abstract: 20 mm thick 6063 aluminum alloy plate were joined by friction stir welding with gas protection.The result showed that the sound joint without lazy S can be achieved.The average tensile strength of welds is 148.9 MPa,which is 81.9% of that of the base metal.Optical microscopy revealed the stir zone presents particularly fined equiaxed gains formed by dynamic recrystallization.The microstructure in TMAZ,in which some degree of dynamic recrystallization occurs,consists of deformed gains.The result shows that lazy S of 6063 aluminum alloy can be eliminated by FSW with gas protection.