The butt welds of 4-mm thick 5A06 aluminum alloy plates were produced by adjustable-gap bobbin-tool friction stir travel with travel speeds of 200, 300, and 400 mm/min in this study. The microstructure was studied using optical microscopy and electron backscatter diffraction (EBSD). Tensile tests and microhardness measurements were performed to identify the effect of the travel speed on the joint mechanical properties. Sound joints were obtained at 200 mm/min while voids were present at different positions of the joints as the travel speed increased. The EBSD results show that the grain size, high angle grain boundaries, and density of geometrically necessary dislocations in different regions of the joint vary depending on the recovery and recrystallization behavior. Specific attention was given to the relationship between the local microstructure and mechanical properties. Microhardness measurements show that the average hardness of the stir zone (SZ) was greater than that of the base material, which was only affected slightly by the travel speed. The tensile strength of the joint decreased with increasing travel speed and the maximal strength efficiency reached 99%.

通过可调间隙线轴工具摩擦搅拌行程以200、300和400 mm / min的行进速度生产了4毫米厚的5A06铝合金板的对接焊缝。使用光学显微镜和电子背散射衍射（EBSD）研究了微观结构。进行拉伸测试和显微硬度测量，以确定行进速度对接头机械性能的影响。随着行进速度的提高，以200 mm / min的速度获得了良好的接头，而在接头的不同位置出现了空隙。EBSD结果表明，晶粒大小，高角度晶界和接头不同区域的几何必要位错密度取决于恢复和再结晶行为。特别注意了局部微观结构和机械性能之间的关系。显微硬度测量结果表明，搅拌区（SZ）的平均硬度大于基材的平均硬度，而后者仅受行进速度的影响很小。接头的抗拉强度随行进速度的增加而降低，最大强度效率达到99％。