In this research, local mechanical tensioning treatment in the form of in-situ rolling tensioning (ISRT) was applied during friction stir welding of AA2024-T3 sheets. Two types of roller configurations were used. First, a single roller located at the rear of the tool which passed over the weld region and secondly, two rollers were located next to the weld zone symmetrically. Subsequently, several experiments comprising residual stress, distortion and fatigue crack growth (FCG) measurements were carried out combined with microstructure, texture, hardness and tensile tests. Results demonstrated that a single roller ISRT effectively diminished residual stress in the nugget zone (NZ) from + 11.7 MPa to −45.3 MPa accompanied by better weld FCG resistance. Apart from residual stress reduction, the improved weld fatigue performance was likely correlated with the modifications of weld microstructure and texture due to rolling tensioning.

中文翻译：

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通过原位滚动拉伸减少残余应力和变形，以提高搅拌摩擦焊 AA2024-T3 接头的疲劳性能


在这项研究中，在 AA2024-T3 板材的搅拌摩擦焊过程中应用了原位滚动拉伸 （ISRT） 形式的局部机械拉伸处理。使用了两种类型的辊子配置。首先，一个滚轮位于工具的后部，穿过焊接区域，其次，两个滚轮对称地位于焊接区旁边。随后，进行了多项实验，包括残余应力、变形和疲劳裂纹扩展 （FCG） 测量，并结合微观结构、织构、硬度和拉伸测试。结果表明，单辊 ISRT 有效地将熔核区 （NZ） 的残余应力从 + 11.7 MPa 降低到 -45.3 MPa，同时具有更好的焊接 FCG 阻力。除了残余应力降低外，焊缝疲劳性能的改善可能与滚动拉伸引起的焊缝微观结构和织构的改变有关。