Abstract A Pin-plunging reinforced refill friction stir spot welding (P-RFSSW) technique was introduced in this study in order to solve the problem of the central void defect and the alclad residues in the weld center associated with conventional refill friction stir spot welding (C-RFSSW) of dissimilar alclad aluminum alloys. The P-RFSSW process is based on promoting the plastic deformation in the weld center owing to the addition of an initial pin plunge stage. The microstructure and mechanical properties of the C-RFSSW and P-RFSSW joints were compared. Results have shown that the P-RFSSW process could eliminate the central void defect and promote the metallurgical bonding and intermixing in the weld. Weld strength was improved when using P-RFSSW compared with the C-RFSSW process, which was attributed to the specific downward extended hook defect into the stronger, thicker 7 series aluminum alloy.

中文翻译：

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Alclad 2219 至 7075 合金的销钉插补增强型搅拌摩擦点焊

摘要 为了解决传统再填充搅拌摩擦点焊存在的中心空洞缺陷和焊缝中心镀层残留的问题，本研究引入了针插式增强再填充搅拌摩擦点焊（P-RFSSW）技术。 C-RFSSW) 的异种合金。P-RFSSW 工艺的基础是由于增加了初始插销阶段，从而促进了焊接中心的塑性变形。比较了 C-RFSSW 和 P-RFSSW 接头的微观结构和机械性能。结果表明，P-RFSSW工艺可以消除中心空隙缺陷，促进焊缝的冶金结合和混合。与 C-RFSSW 工艺相比，使用 P-RFSSW 时焊接强度得到提高，