包铝层对7B04-O铝合金薄板搅拌摩擦搭接性能影响

对2 mm厚的带有包铝层的退火态(O态)7B04铝合金薄板进行搅拌摩擦搭接焊接(Friction stir lap welding, FSLW)。分析包铝层、焊接参数、热处理对FSLW接头质量、微观组织及力学性能的影响。结果表明，焊核中的原始包铝层无法被完全打碎分散，其中前进侧的分散比较明显，而后退侧的包铝层则基本保持了原来状态。通过增加转速或轴肩尺寸，可以有效消除焊核中心的孔隙缺陷，但仍无法使界面处的包铝层充分破碎分散。随着转速增加或焊接工具轴肩尺寸增大，FSLW接头强度提高。包铝层对焊态FSLW接头强度影响不明显，接头强度约为母材强度的94%；淬火后，包铝层对接头强度的影响显著，接头强度仅为淬火态母材的64%。

Effect of Al Clad Layer on Friction Stir Lap Welded 7B04-O Al Sheet

Annealed Al-coating 7B04 Al sheets in thickness of 2 mm are subjected to friction stir lap welding (FSLW). The effect of alclad cladding, welding parameters and heat treatment on the quality, microstructure and mechanical properties of the FSLW joints are investigated. The results show that the original alclad layers can not be completely broken up and dispersed into the nugget zone. The dispersion of the alclad layers in the advancing side is quite obvious, however this is not the case in the retreating side, which is basically maintained as the original state. The pore defect in the nugget zone can be effectively eliminated by increasing the rotation rate and the shoulder size. The tensile strength of the FSLW joint increases with increasing the rotation rate or the shoulder size. The effect of the alclad layer does not show apparent effect on the tensile strength of the welded FSLW joints, and the strength of the joints is about 94% of that of the base material; however, this effect is obvious for quenched joints, the joint strength is only 64% of that of the quenched base material.