热源同轴辅助搅拌摩擦焊工艺特性分析

研究了激光同轴辅助搅拌摩擦焊中激光/搅拌摩擦焊的热量分配对不同系列铝合金焊缝成形、接头力学性能及显微组织的影响，并得到了相应的优化能量分配条件.结果表明，加入激光辅助热源可有效扩大工艺参数窗口，特别是流动性差的5A06和2219铝合金，焊接速度可提升30%以上.激光辅助热源对6061及5A06铝合金焊接接头性能影响较小，对2219铝合金搅拌摩擦焊接头的性能影响明显，焊接热输入增大后，接头性能下降，但总得来说，加入激光辅助热源能够在更小的焊接热输入下获得更高的接头性能.

Investigation on laser coaxially assisted friction stir welding of aluminum alloys

The laser coaxially assisted friction stir welding process of aluminum alloys of different series (5A06, 6061, 2219) was investigated, concentrating on the effects of friction stir heat and laser heat distribution on weld appearance, mechanical properties and microstructure characteristics of the joints. The optimized heat distribution conditions for alloys of different series were obtained. The results show that assisted laser heat can effectively enlarge the process window, especially for 5A06 and 2219 which have low fluidity, can increase the welding speed by 30%. Assisted laser heat has no obvious influence on microstructure of 5A06 FSW nugget zone, but decreases the amount of second phase Mg₂Si in 6601 FSW nugget zone and makes them dispersed, the assisted laser also decreases the amount of strengthening phase CuAl₂(θ) and increases their sizes. For 5A06 and 6061, assisted laser heat has no obvious influence on the joint mechanical properties. However, for the heat treated alloy 2219, assisted laser heat decreases the joint strength, but can obtain high joint strength by welding under low friction stir heat input.