轴肩形貌对铝合金搅拌摩擦焊焊缝金属流动的影响

采用轴肩凹面内渐近线凹槽个数分别为0，2，4，6的搅拌头，并结合镶嵌标示材料方法进行焊接试验，分析轴肩形貌对焊缝金属流动影响.结果表明，随渐近线凹槽数增加，焊核区尺寸及其两侧标示材料向上迁移最大高度先增大后减小，同一焊缝中前进侧标示材料迁移高度始终大于返回侧.使用渐近线凹槽数为4个的搅拌头焊接时可使焊缝中的疏松缺陷消失，且焊核区面积、宽度及其两侧标示材料向上迁移高度最大.适当增大渐近线凹槽数，可增大金属塑化程度及其向下迁移量，改善焊缝成形质量.

Effect of shoulder profile on plastic flow of weld metal in aluminum alloys friction stir welding

The welding tools with shoulder coupled with different number (0, 2, 4, 6) of asymptote grooves were used in friction stir welding aluminum alloys. By using insert tracer technique, the effect of shoulder profile on the plastic flow of weld was studied. The results showed that, with increasing the number of asymptote groove, the size of nugget zone and the height of transferred tracer material on two sides increased firstly and decreased then. Also, the height of material transfer on advancing side was larger than that on retreating side in a same weld. When the tool with a shoulder of 4 asymptote grooves was used, the loose defect disappeared. Meanwhile, the area and width of nugget zone and transferred material height on two sides were the largest. Increasing properly the number of asymptote groove can increase the plastic deformation and the volume of transferred plastic metal, which finally improves the weld quality.