Effect of Ce on microstructure and properties of Mg/Al butt joint welded by gas tungsten arc with Zn–30Al–xCe filler metal

Abstract

AZ31B Mg alloy and 6061 Al alloy are welded by gas tungsten arc welding filling with Zn–30Al–xCe filler metal. The effect of Ce content in Zn–30Al filler metal on microstructure evolution and mechanical properties of the different joints is investigated. The experimental results show that adding appropriate amount of Ce into Zn–30Al filler metal is conducive to improve the microstructure of the joints. The coarse α-Al in the fusion zone of joint is refined with the addition of 0·05 wt-%Ce to the filler metal, accordingly improved the joint strength. However, the microstructure of the fusion zone became coarse again with the addition of 0·08 wt-%Ce in the filler metal. The average tensile strength of the joint with the addition of 0·05 wt-%Ce to the filler metal can reach 132 MPa.

Keywords:

• Mg/Al welding
• Ce
• Intermetallics
• Microstructure evolution

The authors gratefully acknowledge the sponsorships from Program for Changjiang Scholars and Innovative Research Team in University (no. IRT1008) and National Natural Science Funds for Distinguished Young Scholar (no. 51025520).