The effect of laser oscillation welding on porosity suppression for medium-thick Al alloy with high Mg content

The effects of different laser oscillation parameters and oscillation paths on porosity during laser welding of medium -thick high -magnesium aluminum alloys were investigated. The results show that using an infinityshaped oscillation path (A = 1 mm, f = 100 Hz) can effectively suppress keyhole -induced porosity to a low level of 0.3 %. It has been found that oscillation welding can enlarge the opening of the keyhole and reduce the collapse frequency based on observation through high-speed photography. In particular, the infinity -shaped oscillation path significantly suppresses keyhole collapse, with a collapse interval of more than 25 ms, which is attributed to the higher laser beam motion speed, more uniform energy distribution, and slower energy deposition rate. Moreover, the stronger stirring effect and larger motion range of the keyhole under an infinityshaped oscillation path allow bubbles to escape, thus suppressing the formation of pores.