Weld characteristics of narrow gap oscillating laser welding of dissimilar aluminum alloys with hot wire

Narrow gap oscillating laser welding of 6061/2024 dissimilar aluminum alloys with hot wire was carried out. The effects of processing parameters on weld formation were investigated. The results show that increasing the laser power (P) and the wire current (I) can suppress the lack-of-fusion, while increasing the oscillation frequency (f) can effectively eliminate the weld porosity. Furthermore, 20mm-thick joint was fabricated with optimized process parameters and the microstructure and mechanical properties were analyzed. The weld center exhibits an equiaxed microstructure composed of alpha-Al matrix, eutectic on the grain boundary, and point-like precipitation phase in the grain, while the interlayer weld exhibits a gradient microstructure composed of columnar grains, coarse grains, and equiaxed grains. The joint shows good consistency in hardness and tensile properties. The highest tensile strength and elongation are 215 MPa and 9%, which are 69% and 66% of the 6061 aluminum alloy, respectively.