Thermal characterization of aluminum/steel arc-assisted laser welding-brazing process

A three-dimensional nonlinear temperature model was established by finite element modeling analysis during aluminum-steel arc-assisted laser welding-brazing process. Effects of parameters such as heat source distance, welding current and laser heat input on surface temperature distribution and interfacial thermal cycling of welded joints were studied. The result showed that high temperature area on the surface of workpiece presented a “gourd-like” shape distribution with large front and small back, and thermal cycle curve of interface presented a bimodal characteristic. Laser heat input determined the highest peak temperature of vertical interface, and welding current and distance of heat sources mainly affected cooling stage of thermal cycle curve. Increase of peak temperature at interface could increase thickness of intermetallic compound layer, which influenced microstructure evolution of welded joints.Highlights: (1)Addition of low-power arc could improve problem that distribution of single laser heat source was too concentrated and increase residence time in the high-temperature region, so as to promote infiltration and spreading formation of welded joints.(2)Addition of auxiliary arc changed shape of high-temperature region under single laser heat source, and high temperature region with unique “gourd-like” shape appeared in the arc assisted laser welding process.