ABSTRACT
ABSTRACT: The AZ91 magnesium alloy was welded by the GTAW with multi-composite activating fluxes, which contained seven components (MgCl2, CdCl2, NiCl2, CaCl2, CaO, TiO2, and Cr2O3). The composite activating fluxes were designed by the uniform design method. The effects of composite activating fluxes on appearances, hardness, microstructure of welded joint and flow pattern of welding pool were analyzed after A-TIG welding. The results show that the weld penetration can be increased when effected by the all composite activating fluxes. The optimal value can be obtained when the 14th composite activating flux was used, the weld penetration of which is 3.35 times than that weld without flux, and the welded joint appearance is better. The hardness and microstructure are not affected by the 14th composite flux, and the flow pattern of weld pool is inward convection.
