Cold metal transfer welding of aluminium to magnesium: microstructure and mechanical properties

Abstract

This paper reports the procedure to join aluminium A6061-T6 to AZ31B magnesium alloy using Al-5%Si filler by cold metal transfer and pulsed-cold metal transfer processes. The effect of process parameters on the microstructure of weld, nugget/magnesium interface and tensile strength of the joints are analysed. Microstructural analysis shows that the diffusion layer thickness increases with increase in the welding current. The diffusion layer thickness was found to vary depending on the process. Pulsed process resulted in high joint strength compared to conventional method. X-ray diffraction study revealed the formation of different phases in the weld. The welding current, welding speed and the wire-feed rate had significant effect on the joint strength. Failure at the weld/Mg interface was observed.

Keywords:

• Aluminium/magnesium joining
• Microstructure
• Interface
• Tensile strength