Characteristics of Dissimilar Aluminum/Steel Joint Fabricated Via Self-Riveting Friction Stir Lap Welding
Characteristics of Dissimilar Aluminum/Steel Joint Fabricated Via Self-Riveting Friction Stir Lap Welding
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DOI：
10.1007/s12666-021-02327-1
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发表时间：
2021-07-07
影响因子：
1.6
通讯作者：
Zhang, Fenghe
中科院分区：
文献类型：
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作者：
Chen, Yu;Cai, Zhihui;Zhang, Fenghe
采用自铆接搅拌摩擦搭接焊（SR-FSLW）成功地实现了AA 7075铝合金与Q235钢的连接。用AA 7075填充Q235的预钻孔，实现自铆接工艺。此外，AA 7075铆钉被铝/钢螺旋层状结构锁定，并且由于SR-FSLW的机械和冶金冲击，螺旋层状结构由细晶粒和金属间化合物层组成。观察到AA 7075在铆钉内部的循环流动，并提出了一个冲压-挤压-填充-锁紧模型来解释锁紧铆钉的形成机理。与传统的FSLW节点相比，SR-FSLW节点的剪切拉伸性能得到显著提高。此外，增大预钻孔直径有助于增加有效板厚，进一步加强SR-FSLW节点。所有FSLW/SR-FSLW接头均发生在AA 7075侧的焊核区，由于铝/钢弯钩的存在，接头断裂为韧脆混合型断裂。
AA7075 aluminum and Q235 steel were successfully joined by self-riveting friction stir lap welding (SR-FSLW). The pre-drilled holes of Q235 were filled by AA7075, achieving the self-riveting process. In addition, the AA7075 rivets were locked by the aluminum/steel swirl-layered structure, and the swirl-layered structure consisted of fine grains and intermetallic compounds layers due to the mechanical and metallurgical impacts of SR-FSLW. A cyclic flow of AA7075 was observed inside the rivets, and a plunging-squeezing-filling-locking model was proposed to illustrate the formation mechanism of locked rivets. Compared with the traditional FSLW joint, the shear tensile properties of SR-FSLW joint were significantly enhanced. Moreover, enlarging the diameter of pre-drilled hole contributed to the increment in the effective sheet thickness, strengthening the SR-FSLW joint further. All FSLW/SR-FSLW joints were failed in the nugget zone of AA7075 side, and a mixture of ductile-brittle fracture was observed due to the existence of aluminum/steel hook.