Study of Microstructure and Properties of AZ91 Magnesium Alloy Welded Joint with Magnetic Field and TiO2 Activated Flux

In order to improve the weldability and bearing capacity of AZ91 magnesium alloy welded joints, magnetic field active flux were added in TIG welding process. process, parameters unchanged, coating amount was adjusted. The formability, mechanical properties, microstructure joints under different amounts activated analyzed, crystallization nucleation characteristics molten pool discussed. experimental results reveal that combined effect has a significant on increasing penetration promoting properties. When is 3 mg/cm2, highest joint obtained, which 141% without flux. Meanwhile, properties reach maximum, tensile strength 292 MPa, elongation 11.2%, weld zone hardness 75.6 HV (0.5 Kgf). TiO2 does not change phase composition grain orientation metal but can affect size. average size an mg/cm2 18.2% smaller than 1 mg/cm2.