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采用圆台形搅拌针和倒圆台形搅拌针分别对2 mm厚的AZ61B镁合金材料进行了搅拌摩擦焊(FSW)搭接试验,研究了搅拌针形状及旋转速度对搭接接头迁移界面的影响。研究结果表明,倒圆台形搅拌针作用下的搭接接头焊核区出现明显的分层现象,而圆台形搅拌针作用下的搭接接头焊核区分层现象不明显,并且前者的接头界面迁移高度较后者的低。旋转速度对接头的焊核区形貌及界面迁移高度也有重要的影响:随着旋转速度的增大,焊核区尺寸也逐渐增大;当焊速为定值时,随着旋转速度的增加,界面迁移高度也随之增加,当旋转速度超过一定值时,即圆台形搅拌头的旋转速度大于1200 r·min~(-1)或倒圆台形搅拌头的旋转速度大于1100 r·min~(-1)时,界面迁移高度将保持恒定或减小。剪切拉伸性能测试结果表明,断裂均起源于迁移界面,然后沿着垂直于载荷方向断裂;界面迁移高度越低,接头抗剪强度越高;与圆台形搅拌针相比,倒圆台形搅拌针获得的接头最大抗剪强度提高了10%。
Friction stir welding (FSW) lap test was conducted on the 2 mm thick AZ61B magnesium alloy by using a truncated cone-shaped and a truncated cone-shaped stirring pin respectively. The effects of the shape of the pin and the rotation speed on the interface of the lap joint were studied. The results show that there are obvious delamination in the weld zone of lap joint under the action of the truncated table-shaped stirring pin, while the phenomenon of delamination in the weld zone of the lap joint under the action of the truncated cone-shaped stirring pin is not obvious, and the former joint interface The migration height is lower than the latter. The rotation speed also has an important effect on the weld nugget topography and interface migration height of the joint: as the rotation speed increases, the size of the nugget core also gradually increases; when the welding speed is constant, as the rotation speed increases , The interface migration height also increases. When the rotation speed exceeds a certain value, that is, the rotation speed of the truncated cone-shaped mixing head is greater than 1200 r · min -1 or the rotation speed of the truncated-cone stirring head is greater than 1100 r · min ~ (-1), the interface migration height will remain constant or decrease. The shear tensile test results show that the fracture originated in the migration interface and then ruptured along the direction perpendicular to the load. The lower the interface migration height, the higher the shear strength of the joint. Compared with the truncated cone-shaped pin, Needle obtained connector maximum shear strength increased by 10%.