Research On A-TIG Welding And Diffusion Bonding Of Magnesium Alloys

In recent years, requirement of light weight made application of magneium alloys increasing rapidly in aeronautic, aerospace, automobile and telecommunication industries, and welding technology of magnesium alloys is the key technology and current research hotpot for the application development of magnesium alloys. In the paper, effects A-TIG welding on of the weld bead penetration, microstructure and the capability of the magnesium alloy joints are studied by using the remelting, built-up welding and butt welding, and effects of the diffusion bonding on the microstructure and mechanical properties of of magnesium alloys are also studied.For the remelting of the AZ31 magnesium alloy, the weld bead penetration without activating fluxes increased with the increasing welding electricity, and the weld width also increased slowly. Effects of activating fluxes and their additions on weld forming during the TIG welding of AZ31 magnesium alloy are studied. Compared with weld without flux, the weld bead penetration and weld depth to width ratio are greatly increased after applied with flux of TiO2,SiO2,Cr2O3,CdCl2 and CaCl2 for magnesium alloy, and the effect of flux CdCl2 is the greatest. However the flux fluoride is not useful for the weld penetration,and weld with flux of CaF2 is cracked. For the remelting tests of thick AZ31 magnesium alloy plates, most of the fluxes increase the weld penetration, chloride fluxes can increase the weld penetration greatly, and effects of flux CdCl2 and MgCl2 are the greatest.During the built-up welding of AZ31 magnesium alloy, oxide fluxes can increase the weld penetration slightly, chloride fluxes can increase the weld penetration greatly. Effects of fluxes on increasing the weld penetration are more greatly for AZ61 magnesium alloy.For AZ31 and AZ61 magnesium alloy, effects of activating fluxes with hybrid component on weld forming in the A - TIG butt joint welding of are studied. Compared with weld without flux, the weld penetration is greatly increased. Compared with that without flux, the microstructure and the hardness distribution of weld with flux H4 (40%CdCl2,20%TiO2,20%SiO2,20%Cr2O3) does not change significantly,but the heat affected zone is wider. The effect of flux H4 on the weld penetration is the greatest for AZ31 magnesium alloy, and the penetration of the...