通过3 mm厚5A90铝锂合金激光焊工艺试验,采用无量纲背宽比R表征焊缝截面,较系统地研究了激光功率、焊接速度和离焦量对焊缝成形的影响规律。结果表明,焊缝背宽比随激光功率的增大而增大,随焊接速度的增大而减小,且在离焦量为0～+1mm范围内达到最大。激光功率和焊接速度的合理匹配,可以获得较好的焊缝成形。 Through 3 mm thick 5A90 Al-Li alloy laser welding process test, the non-dimensional aspect ratio R was used to characterize the weld cross section. The influences of laser power, welding speed and defocusing amount on the weld formation were systematically studied. The results show that the weld back width ratio increases with the increase of laser power, decreases with the increase of welding speed, and reaches the maximum within the range of 0 ~ +1 mm. Laser power and welding speed of a reasonable match, you can get a better weld forming.