Refill friction stir spot welding is a solid-state spot-welding technique suited to lap joining of thin aluminium sheets, including difficult-to-weld 2xxx series alloys that are prone to hot cracking during fusion welding processes. Long welding time is an ongoing challenge that hinders industrial adoption of the process. To address this, the present study explores much shorter welding times than those previously reported in the literature and assesses the impact on joint quality. Joints of 1.8 mm thick AA2024-T3 sheet were produced with welding times from 3 s, down to 0.75 s and rotational speeds of 1000 rpm to 2500 rpm. Defect formations within the welds were studied with the aid of optical microscopy. The mechanical properties were evaluated using tensile lap shear testing and microhardness mapping, and failure modes were characterised using scanning electron microscopy. Various weld defects were found at all welding times and rotational speeds, and the defects enlarged with decreasing welding time and increasing RS. The highest lap shear strength of 9.21 kN was achieved with a welding time of 3 s and rotational speed of 2000 rpm; lap shear strengths of 7.02 kN and 6.37 kN were achieved for 1.5 s and 0.75 s welds, respectively.

补充填充搅拌摩擦点焊是一种固态点焊技术，适用于薄铝板的搭接连接，包括难以焊接的 2xxx 系列合金，这些合金在熔焊过程中容易产生热裂纹。焊接时间长是一个持续的挑战，阻碍了该工艺的工业应用。为了解决这个问题，本研究探索了比之前文献报道的焊接时间短得多的焊接时间，并评估了对接头质量的影响。1.8 毫米厚的 AA2024-T3 板材接头的焊接时间从 3 秒降至 0.75 秒，转速为 1000 rpm 至 2500 rpm。借助光学显微镜研究焊缝内的缺陷形成。使用拉伸搭接剪切测试和显微硬度图评估机械性能，并使用扫描电子显微镜表征失效模式。在所有焊接时间和转速下都发现了各种焊接缺陷，并且缺陷随着焊接时间的减少和RS的增加而扩大。焊接时间为3 s，转速为2000 rpm时，搭接剪切强度最高为9.21 kN；1.5 s 和 0.75 s 焊缝的搭接剪切强度分别为 7.02 kN 和 6.37 kN。