A Novel Technique is proposed in this investigation called Double Stage Friction Stir Spot Extrusion Welding (DSFSSEW). It is carried out in two stages by using a pin-shoulder tool in step 1 and a pin-less tool in step 2 to investigate the joint strength of the AA1050 sheet. The advantage of this new double-stage FSSEW technique compared to the classical FSSW led to the elimination of the keyhole, which is an intrinsic flaw of the Friction Stir Spot Welding (FSSW) process resulting in higher mechanical joint properties. The impact of the plunge depth and tool revolving speed on the characteristics of the bond was investigated. The height of the extruded aluminium was increased by increasing the tool rotation speed and the plunging depth which was the effective variable. The joint strength was increased in step 2. The two sheets are bonding together at a line of the interface by a mechanical interlock formed by a continuous metal flow of aluminium extrusion that is free of flaws. There were two mechanisms of failure in the studied samples: cleavage of the aluminium metal at the tool trace and shearing of the extruded aluminium, respectively. The suggested method is novel and has a great potential for future investigation, this work might pave the way for studies of welding with additional alloys, both similar and dissimilar to those already studied.

这项研究提出了一种称为双级搅拌摩擦点挤压焊接（DSFSSEW）的新技术。分两个阶段进行，步骤 1 中使用销肩工具，步骤 2 中使用无销工具，以研究 AA1050 板材的接合强度。与传统的 FSSW 相比，这种新型双级 FSSEW 技术的优势在于消除了匙孔，这是搅拌摩擦点焊 (FSSW) 工艺的固有缺陷，从而实现了更高的机械接头性能。研究了切入深度和工具转速对结合剂特性的影响。通过增加刀具转速和有效变量切入深度来增加挤压铝的高度。步骤 2 中的接合强度有所增加。两块板材通过机械联锁在界面线上粘合在一起，该机械联锁由无缺陷的铝挤压连续金属流形成。研究的样品有两种失效机制：分别是工具痕迹处铝金属的裂解和挤压铝的剪切。所提出的方法是新颖的，对于未来的研究具有巨大的潜力，这项工作可能为使用与已经研究的合金相似和不同的附加合金进行焊接的研究铺平道路。