Gas Tungsten Arc Welding of Dissimilar Magnesium Alloys as AZ31 with AZ61

The AZ31 and AZ61 plates in 3 mm thick plates are welded with AZ31 and AZ61 welding wires by TIG method.The influence of welding wires on the strength of welded joints of AZ31 and AZ61 magnesium alloy plates was investigated.The appearance shape,microstructure and patterns of welded joints were analyzed as well as the mechanical properties test by means of OM,SEM,X-ray diffraction and etc.The result showed that the appearance shape was good with weather AZ31 or AZ61 welding wire.The welded zone was identified to be composed of α-Mg and β-Mg17Al12 phases.The heat affected zones exist both in AZ31 and AZ61 joints,with grains coarser than base metal.Relative to AZ61 welding wire,using the AZ31 welding wire tends to get a coarse grain region of little width,and a fracture point closer to the center line of welding seam,with tensile fracture strength of 161MPa leading to a 64% strength of the AZ31 base metal.With the AZ61welding wire,a coarse grain region of more width and a fracture point a little far from the center line are happened,the strength of the joints reaches to 210MPa,84% of that of its AZ31 base metal.