The evolution of microstructure and mechanical properties of AZ31 magnesium alloy joined by TIG welding

Magnesium alloys are being extensively demanded in airplane and space industry, biomedical product manufacturing and particularly in automotive industry because of their low density, high corrosion resistance and good strength properties. However, the main limitation in their use during manufacturing is the problems encountered when they are welded, such as cracks which occurred in the welded metal, thus decreasing the mechanical properties. The aim of this study is to determine to effect of the welding speed on AZ31 magnesium alloy joined via TIG welding. Therefore, AZ31 magnesium alloy was welded at three different welding speeds in this study. Afterwards, microstructure and mechanical properties of the AZ31 magnesium alloy welded at different speeds were analyzed. Macro and microstructures of the samples manufactured by welded joints were analyzed and tensile, hardness and bending tests were performed to the samples. The results suggested that heat input, which decreased by increasing welding speed, effected both the microstructure and the mechanical properties.