Effects of SiC ceramic particles on microstructures and mechanical properties of gas tungsten arc welded AZ31magnesium alloy with Cr₂O₃ flux coating

Abstract

The effects of SiC ceramic particles on the macromorphologies, microstructures and mechanical properties of tungsten inert gas welded AZ31 magnesium alloy joints with Cr₂O₃ flux coating were investigated. The results showed that an increase in the amount of SiC ceramic particles contained in the Cr₂O₃ flux coating led to the gradual decrease in weld penetrations. The weld penetrations of all welded seams with flux coatings were obviously higher than those without flux coating. Grain refinement was obtained in the welded seams when SiC ceramic particles were added in the Cr₂O₃ flux coating. With an increase in the amount of SiC ceramic particles, the ultimate tensile strength value of the welded joints increased at first and then decreased. Moreover, the microhardness of the fusion zone increased gradually with an increase in the addition of SiC ceramic particles in the Cr₂O₃ flux coating.

Keywords:

• AZ31 magnesium alloy
• Tungsten inert gas welding
• Cr₂O₃ flux coating
• SiC ceramic particles
• Microstructure
• Mechanical property

This research was financially supported by Fundamental Research Funds for the Central Universities of China (grant no. CDJZR11135501) and a Fundamental Research Funds for the Central Universities (grant no. CDJXS10131155) and a Natural Science Foundation Project of CQ CSTC (grant no. cstc2012jjA50002) and supported by Sharing Fund of Chongqing University’s Large-scale Equipment (grant no. 2011063023).