采用PFL-1A型激光加工送粉器和新型双层送粉喷嘴,在(Slab)CO2激光器上对一种较常用的高强度铝合金A2219进行焊接实验。研究了粉束落点相对激光光斑位置变化、送粉与焊接的相对方向对送粉时焊接过程和粉末利用率的影响。并研究了激光功率、离焦量和焊接速度的合理匹配。结合高速摄像仪和光束光斑诊断仪的观察数据对实验现象和结果进行了合理的分析,并给出优化的工艺参数区间。实验表明,只有当粉束作用在靠近熔池结晶前沿,偏离光斑后侧0.5～1　mm的区域,粉束才能有效地进入熔池;当送粉量一定时,需要相应的功率、功率密度和焊接速度匹配,粉束才能有效利用,得到理想的焊缝。通过优化工艺参数,成功获得了具有理想余高、成形良好、焊接过程稳定的焊缝。

A widely used high strength aluminum alloy A2219 is welded with CO2 laser adopting a new nozzle and PFL-1A powder deliver machine. The influences of the parameters of the nozzle and the laser on the welding process and the utilization ratio of the powder are researched during laser welding with powder. The observed result of the experiment is analyzed on the base of the picture collected by the high-speed camera together with the data from the Laserscope UFF100, and the optimized parameters ranges are obtained. The experiment results show that, only when the powder beam aims at the area that is near the crystallization edge, and 0.5～1 mm away from the facula, it can be sure to enter the weld pool efficiently. When a certain amount of powder is given, welding speeds need to be matched with proper power and power density to make sure that the powder can be utilize availably. Finally, the well-formed weld with proper exceeded height as well as the stable welding process can be obtained through optimizing the parameters.