Low-Power Laser/TIG Hybrid Welding Process of Magnesium Alloy with Filler Wire

In the welding process of magnesium alloy, evaporative loss of alloying elements will induce welding defects and reduce the mechanical properties of weld joint. In this article, low-power laser/arc hybrid welding process of magnesium alloy with filler metal is studied to resolve this problem. Under the optimal welding parameters, weld joint with good formation and high quality can be obtained. The feeding modes of filler wire and the effects of welding parameters on weld joint are studied. The grain size of fusion zone and heat-affected zone (HAZ) become uniform, and the tensile strength of welding joint reaches about 95% of base metal. Besides, the arc plasma behaviors and plasma spectra are investigated, and the results show that the arc plasma expands and the electron temperature of arc plasma decreases, but the electric conducting route concentrates and the energy density of arc plasma enhances, which improves the welding penetration significantly.