Investigations on Laser-TIG Hybrid Welding of Magnesium Alloys

Abstract:

This paper presents results of recent investigations on the weldability of several wrought (AZ31, AZ61) and cast magnesium-based alloys (AZ91) by laser-TIG welding process. The investigations showed that magnesium alloys can be easily welded by laser-TIG welding. The grain of the fusion zone was finer than that of in base metal. The width of the heat-affected zone welded by laser-TIG welding process was obviously narrower than that of welded by TIG. Besides, with the Al content of magnesium alloys increasing, the width of the heat-affected zone (HAZ) was increased，as well as the content of β phase(Mg17Al12). The hardness in the fusion zone (FZ) and in HAZ of AZ61 and AZ91 has a large change to the base metal due to the existing of β phase, while no change relative for AZ31. It results from above discussing that laser-TIG welding is an excellent welding process for magnesium alloys.