1 Introduction
Magnesium alloys have low density, high-specific
strength, excellent dimensional stability and good energy
absorption. These alloys are also recyclable, making
them a kind of green metallic structural material for the
21st century[1−2]. Mg-Li alloys with a density smaller
than normal magnesium alloys have attracted much
attention among researchers for their potentially broad
applications in aerospace, transportation, electronic and
military industries[3]. Consequently, researchers have
done a lot of work on the welding of magnesium
alloy[4−6], as joints are important for advanced materials
with wide applications.
Because Mg alloys have a low melting point, high
thermal conductivity, electrical conductivity and thermal
expansion coefficient, they are chemically active and
readily oxidized[7−8]. ASAHING[6] pointed out that
due to the deformation during welding process, the
solidification cracks of TIG welded magnesium alloy
were restrained[9−10]. CAO et al[11] found that many