MIG welding is 103 up to 104 higher than that of aluminum, which
leads to the droplet be overheated easily during MIG welding of Mg
alloys because the possible temperature interval on the droplet is
very small. The overheated droplet explodes sensitively due to the
high vaporization pressure of Mg, resulting in a great spatter and a
very unstable process without a secure drop detachment. Thus, MIG
welding of Mg alloys is very difficult. Only two special MIG welding
methods obtained sound Mg joints: the triggered short-circuiting
arc welding developed by Wohlfahrt et al. (2003) and the AC-MIG
welding presented by Song et al. (2010). This situation hampered
the development of laser–MIG hybrid welding of Mg alloys.
As the unstable arc could be stabilized by laser–arc interaction
during the hybrid welding, Gao et al. (2009a) had reported a preliminary
result to obtain one accepted joint by laser–MIG hybrid
welding of AZ31 Mg alloy. It suggested the unstable problem in the
laser–MIG hybrid welding of Mg alloys might be overcome by optimizing
the interaction of two heat sources. However, there lack
comprehensive investigations into effects of welding parameters
on process characterization and joint performance. This article aims
to deepen the understanding of laser–MIG hybrid welding of Mg
alloys by presenting more experiment results.