The investigation of the combinability of az31 magnesium alloy with gtaw

In this study, AZ31 magnesium alloy pair is combined with different protective gas atmosphere by GTAW welding method at different current values. Argon, Helium, Argon-Helium are used as protective gas. Welded points are carried out under these protective gas atmospheres at the current values of 130 A, 140 A, 150 A, 160 A microstructures of the welded joints of the welded specimens are investigated by optical microscopy (OM), scanning electron micsroscopy (SEM) and energy dispersive X-Ray (EDS) methods. The mechanical strengths of welded joints are determined by micro hardness measurements ands tensile tests. It's found that different microstructures are formed according to different protective gas and heat input changes. It's observed that the width of the weld zone and grain size increase, as the heat input increases. The highest micro hardness value is measured at 60 HV in the sample welded at a current value of 130 A under argon protective gas atmosphere. Also, the highest tensile strentgh value is measured at 130.19 N/mm2 in the welded specimen at a current value of 130A under a helium protective gas atmosphere. It's found that the average tensile strength values of the specimens, welded with low heat inputs are generally high. Keywords: Magnesium Alloy, AZ31, GTAW, Protective Gas, Tensile Strength, Microhardness