High-frequency oscillating laser-arc hybrid welding of 8-mm-thick high-strength aluminum alloy through synchronous wire-powder feeding

Abstract

Laser-arc hybrid welding of high-strength aluminum alloy faces the problems of serious evaporation and burning loss of alloying elements, which cause instability on the plasma and melt flow, and reduce weld mechanical properties. In the current study, both high-frequency beam oscillation and synchronous wire-powder feeding were adopted to solve the above problems during the hybrid welding of 8-mm-thick AA2219 aluminum alloy. The results showed that compared with none-oscillating hybrid welding, wire-powder synchronous oscillating hybrid welding reduced weld porosity from 10.7% to 0.7%, and increased the ultimate tensile strength and elongation by 12% and 72% respectively. The feeding of Mg powder promoted the formation of fine Al2CuMg strengthening phase by substituting the block Al2Cu eutectic. Besides, the oscillating laser at frequency of 250 Hz induced the strengthened stirring of molten pool, which benefited to break and inhibit the growth of dendrite grains, capture bubbles and solidified pores, and reduce the probability of bubble formation due to the instability and collapse of laser keyhole.