The present research introduces a unique concept of scarf joint technique in friction stir welding (FSW) of aluminum alloy AA 6061-T6 plates and an investigation on weld quality. A new joint configuration with two distinct scarf angles (75° and 60°) was considered in this study. The various aspects of welding were compared with contemporary simple square butt (SSB) joint configuration. Welding was carried out at a constant tool rotation speed (TRS), tool traverse speed (TTS) and tool tilt angle of 1100 rpm, 2 mm/s and 2°, respectively. The results are analyzed in terms of force and torque distribution, microstructure, macrostructure, and mechanical property perspective for different joint configurations. The study reveals the minimum amount of force and torque at 60° scarf angle joint configuration compared to that of square butt joint configuration. Macro study shows that all the joints were defect-free, and a prominent onion ring was present in the lower portion of the weld nugget (WN). Fine equiaxed grains with a minimum average grain size diameter of 6.82 μm were obtained in the WN of scarf joint configuration (SJC). The maximum ultimate tensile strength (UTS) and maximum average NZ hardness of 267 MPa and 83.82 HV_0.1 were obtained in SJC3 at a scarf angle of 60°. It has been observed from the investigation that the joint efficiency increases from 72.5% (SSB) to 86% (SJC3) at a 60° scarf angle. This unique characteristic may lay an impetus on probable joint strength enhancement technique without increasing the production cost.

本研究在铝合金 AA 6061-T6 板的搅拌摩擦焊 (FSW) 中引入了一种独特的斜接接头技术概念，并对焊缝质量进行了调查。本研究考虑了一种具有两个不同斜角（75° 和 60°）的新关节配置。焊接的各个方面与当代简单方形对接 (SSB) 接头配置进行了比较。焊接在恒定的工具旋转速度 (TRS)、工具移动速度 (TTS) 和工具倾斜角分别为 1100 rpm、2 mm/s 和 2° 下进行。对不同关节配置的力和扭矩分布、微观结构、宏观结构和机械性能方面的结果进行了分析。研究表明，与方形对接接头配置相比，60° 斜接角接头配置的力和扭矩最小。宏观研究表明，所有接头均无缺陷，并且在焊核 (WN) 的下部存在突出的洋葱圈。在斜接接头配置 (SJC) 的 WN 中获得了最小平均粒径为 6.82 μm 的细等轴晶粒。最大极限抗拉强度 (UTS) 和最大平均 NZ 硬度为 267 MPa 和 83.82 HV在 SJC3 中以 60° 的斜角获得_{0.1 。}从调查中观察到，在 60° 斜接角时，接头效率从 72.5% (SSB) 增加到 86% (SJC3)。这种独特的特性可能会在不增加生产成本的情况下推动可能的接头强度增强技术。