A novel material tracing technology was proposed using ER2319 aluminium alloy welding wire as the tracer material to study the material flow behaviour at different positions of friction stir welded 6061-T6 aluminium alloy joint. Having been influenced by temperature and driving force of the tool, the displacement of all the tracer materials deposited behind the original position during welding decreased gradually from top to bottom of the stir zone (SZ). The advancing side (AS) and the retreating side (RS) of the SZ are dominated by the shear action and the extrusion action, respectively. The extrusion force and friction force are the driving forces for material flow during friction stir welding. The material flowed downward at the AS and upward at the RS in the vertical plane of the joint, while the material of the SZ flowed to the back of the tool through the RS in all the horizontal planes of the joint. The flow path of tracer material in most positions of the SZ is arc shaped, however, it is a complex curve in the SZ bottom at the AS due to the poor material flowability. The rotation angle of the tracer material decreased from AS to RS of the SZ and from top to bottom of the SZ.

提出一种以ER2319铝合金焊丝为示踪材料的新型材料示踪技术，研究搅拌摩擦焊6061-T6铝合金接头不同位置处的材料流动行为。受温度和工具驱动力的影响，焊接过程中沉积在原始位置后面的所有示踪材料的位移从搅拌区（SZ）的顶部到底部逐渐减小。SZ 的前进侧 (AS) 和后退侧 (RS) 分别以剪切作用和挤压作用为主。挤压力和摩擦力是搅拌摩擦焊过程中材料流动的驱动力。材料在接头的垂直平面中在 AS 处向下流动，在 RS 处向上流动，而 SZ 的材料在接头的所有水平面上通过 RS 流到工具的背面。SZ大部分位置的示踪材料流道呈圆弧形，但由于材料流动性差，AS在SZ底部呈复杂曲线。示踪材料的旋转角度从 SZ 的 AS 到 RS 以及从 SZ 的顶部到底部减小。