Welding technology and microstructure of tungsten inert-gas welded magnesium alloy

Tungsten inert-gas(TIG) welding was used to weld deforming magnesium alloy AZ31B.The difference between TIG welding with filler metal and without filler metal was studied.Microstmcture,tensile and fatigue strength of the weld with different filler metal were investigated.The result showed that compare with TIG welding without filler metal TIG welding with filler metal has improved tensile strength.For different filler metal,the eutectic phase will increase with increase of aluminum content in filler metal.The increasing of eutectic will reduce the joint strength because of the increasing of Mg₁₇Al₁₂,and on the other hand it will improve the strength for the solution of aluminum into α-Mg.From the study of fracture,the mixed fracture is observed.