Partially Melted Zone in Mg-Al Type Alloy After Gas-tungsten Arc Welding

The gas-tungsten arc (GTA) welding behaviors of the commercial AZ91 magnesium alloy were examined in terms of microstructure characteristics. This study focused on the effects of the GTAW process parameters (like welding current, welding speed and method of additional cooling of the welded samples) on the size of the fusion zone (FZ) and partially melted zone (PMZ). The PMZ morphology of the eutectic regions changed from less to more divorced in the direction from the FZ to the base metal. The largest PMZ was obtained at a low welding speed (3.33 mm/s) and without additional water cooling of the samples.