Weld formation mechanism of fiber laser oscillating welding of dissimilar aluminum alloys

The development of high power galvanometer provides an opportunity to improve the weld formation of dissimilar aluminum alloys. In this paper, the influence of oscillating frequency and amplitude on weld formation of 6061/2A12 aluminum alloys was studied. Laser induced breakdown spectroscopy (LIBS) was used to detect the distribution of copper in weld section to explore the flowing of melting pool. The results showed that weld morphology became smooth and uniform with the increase of oscillating frequency and amplitude, reaching the optimized at frequency of 200 Hz and amplitude of 0.4 similar to 1.2 mm. The front weld width increased and the backside weld width decreased gradually with the oscillating frequency and amplitude increased. The weld segregation was improved in laser oscillating welding, expressed by the mixing uniformity. It was mainly depended on oscillating frequency, and increased with the oscillating frequency increased. When increasing oscillating frequency or amplitude, the stirring intensity of the melting pool was increased. The melting pool was accelerated and mixed more evenly. Thus, the Cu is evenly distributed in the weld, and it can be detected on the side near 6061 base material.