Gas tungsten-arc filler welding of AZ31 magnesium alloy

Optical microscopy and scanning electron microscopy (SEM) were used to examine the microstructure and fracture of AZ31 magnesium alloy joint welded by automatic gas tungsten-arc filler (GTAF) welding process with AZ61 wire. More endeavors have been put on investigating the effect of filler wire on microstructure and performance of welded joint. The result showed that the grain size in heat-affected zone (HAZ) of GTAF welded joint holds significant variety compared with that of GTA welded joint (without filler wire). The modification of microstructure in HAZ has changed the fracture location as well as the ultimate tensile strength (UTS) of joint in tensile test.