轴肩压入量对2524铝合金FSSW接头组织性能的影响

对2524铝合金薄板进行搭接搅拌摩擦点焊试验,探究轴肩压入量对FSSW焊接接头组织与性能的影响。结果表明:随压入量增加,飞边增多,上板减薄严重,有效连接宽度逐渐增大,有效厚度逐渐减小;焊核区硬度随压入量增加逐渐增大;在单向拉伸试验中,接头最大剪切载荷随压入量增加,先增大后减小,压入0.6 mm时达到最大值,为4 092 N;接头存在低压入量剪切焊核断裂和高压入量撕裂上表面断裂两种模式;断口存在大量韧窝和细小弥散分布的第二相粒子,接头呈韧性断裂。

Effect of shoulder plunge depth on microstructure and properties of 2524 aluminum alloy friction stir spot welding joints

In this paper,the friction stir spot welding(FSSW)joints experiment of 2524 aluminum alloy sheet was carried out to explore the influence of plunge depth on the microstructure and performance of shoulder. The results show that with the increase of radial feed quantity,the flash increases,the thickness of upper plate decreases seriously,the effective connection width increases gradually,and the effective thickness decreases gradually. The microhardness of weld nugget zone increases with the increase of plunge depth. In the unidirectional tensile test,the shear strength of the joint increases first and then decreases with the increases of the plunge depth,reaching the maximum value of 4 092 N when the plunge depth is 0.6 mm. There are two fracture modes in the joints:shear weld nugget zone fracture at low plunge depth and upper surface fracture at high plunge depth. There are a lot of dimples and small dispersed second-phase particles in the fracture,ductile fracture can be observed on the joint.