Determination of Minimum Corrosion Conditions for the Stir Zone of Friction Stir Welded AZ31B Magnesium Alloy

Joining of magnesium alloys is increased because of its superior properties like light weight and high specific strength. Compared to fusion welding process, friction stir welding (FSW) is widely adaptable to join magnesium and its alloy. In the FSW joint, grains are very fine in stir zone (SZ) compared to the other zones. This leads to severe corrosion attack at the stir zone. The chloride ion concentration, pH value and immersion time are reported to be the more influencing parameters on corrosion attack. The present work aims to identify the minimum corrosion conditions in the SZ of friction stir welded AZ31B magnesium alloys by statistical tools such as design of experiments (DoE), analysis of variance and response surface methodology (RSM). From the results, it is found that the chloride ion concentration has a greater influence on corrosion rate than the other two parameters.