搅拌摩擦焊接过程中搅拌头转速对材料流动的影响

使用有限元方法模拟了不同搅拌头转速下，搅拌摩擦焊接过程中Al6061～T6材料的三维流动，以及材料流动与搅拌头转速的关系，结果表明，在搅拌摩擦焊接过程中，后退侧的材料流动较前进侧更为剧烈，并且随着搅拌头转速的增加，材料流动也会得到不同程度增强，搅拌头前方的材料在搅拌头的推动作用下向上涌起，被旋推到搅拌头后方并向下运动，该过程的周而复始是促使搅拌摩擦焊接顺利完成的主要原因，等效塑性应变等值线的形状与材料热影响区，热力影响区以及搅拌区的边界形状具有较好的对应关系，随着搅拌头转速的增加，等效塑性应变随之增加。

EFFECT OF ANGULAR VELOCITY OF THE PIN ON MATERIAL FLOW DURING FRICTION STIR WELDING

Finite element method was used to model the material flow of alloy Al 6061-T6 in friction stir welding (FSW) process and the relationship between the material flow and the angular velocity of the pin. The results show that the material flow on the retreating side is faster than that on the advancing side. With the increase of the angular velocity, the material flow becomes faster. The material in front of the pin moves upward due to the extrusion of the pin and is forced to rotate around the pin and then, the material behind the pin is forced to move downward, which makes the friction stir process continuing. The equivalent plastic strain correlates well with the boundaries of the different microstructure zones. With the increase of the angular velocity, the equivalent plastic strain is increased.