Microstructure Evolution of AZ91 Magnesium Alloy Welded Joint under Magnetic Field and NiCl2 Activated Flux

As the lightest engineering materials, magnesium alloys have been widely used. Because of specific chemical and physical characteristics, weldability alloy is poor. Adopting suitable welding technology improving quality welded joints key to their successful application. According previous research data, it was found that combined action magnetic field activated flux has a positive effect on improving-welding efficiency properties joint, butanalysis microstructure evolution insufficient. In this paper, AZ91 by TIG with external longitudinal AC field. The phase composition were investigated. experimental results revealed joint not changed due introduction flux, growth patterns grain in weld seam heat-affected zone different. When amount 3 mg/cm2 field, size finest, which 18.96 μm. However, larger than base metal. crystallographic characteristics boundaries metal both LAGBs. messier misorientation angle. Under crystallization nucleation condition molten pool changed, formation twins promoted, crystal could selectively grow parallel (0001) basal plane.