搅拌头形状对搅拌摩擦焊接头中洋葱环形貌的影响

Influence of Tool Shape on Morphology of Onion Rings in Welded Joint During Friction Stir Welding

采用铝箔作为标示材料,用不同螺纹旋向、不同轴肩直径的搅拌头进行了搅拌摩擦焊试验。结果表明,搅拌针表面为左旋螺纹时,洋葱环中心出现在焊缝的中下部,搅拌针表面为右旋螺纹时,洋葱环中心出则现在焊缝的上部;洋葱环花纹是由搅拌针附近的塑性金属在搅拌针表面螺纹的驱动下沿厚度方向迁移并在搅拌针端部或根部形成挤压区所造成的;轴肩较大的搅拌头有利于塑性金属在焊缝厚度方向上的迁移,洋葱环更易于在厚度方向上扩张。

Using aluminum foils as a tracer materials,aluminum alloy was welded by friction stir welding under different threaded direction pin and diameter shoulder.The results show that the center of onion rings appears at the bottom of the weld when the weld is conducted using left hand thread pin,the center of onion rings appears at the top of the weld when the weld is conducted using right hand thread pin;the onion rings pattern is caused by the extrusion zone,which appears at the tip of the pin or the root of the pin where plastic metal around the pin transfers in the weld thickness direction driving by the thread.The stirrer with bigger shoulder contributes to the transformation of plasticity in the direction of weld thickness,it is easier for onion rings to expand in the weld thickness direction.