Evolution of microstructures and mechanical properties of AZ31B magnesium alloy weldment with active oxide fluxes and GTAW process

TLDR: In this article, the effect of active oxide fluxes with gas tungsten arc welding on the microstructure and mechanical properties of AZ31B magnesium alloy weldment was investigated.

Abstract: In this study, the effect of active oxide fluxes with gas tungsten arc welding on the microstructure and mechanical properties of AZ31B magnesium alloy weldment was investigated. The gas tungsten arc welding process through a flux spray layer was applied to an AZ31B magnesium alloy sheet to produce a bead-on-plate specimen. Oxide (TiO2, SiO2, Fe2O3, Al2O3, and ZrO2) powders were used as the activating fluxes. The macrographs and micrographs of the weld beads were examined using an optical microscope and a scanning electron microscope. The specimens with SiO2 and Fe2O3 fluxes had high depth-to-width ratio welds, followed by those with TiO2 and ZrO2 fluxes and while that with Al2O3 flux had the low ratio weld. The use of 70 A welding current for the specimens with different fluxes produced complete penetration, whereas the specimen without any flux required a 90 A welding current to produce complete penetration. The weld bead microstructure was affected by the activating fluxes, which created different ther...