Study on the Mechanical Properties of Dissimilar Friction Stir Welding of AA 7075 T6 and AZ31B Alloys

In this study, the welding properties of the AA 7075 T6 and AZ31B magnesium sheets were studied by using friction stir welding (FSW). For this purpose, the present work was investigate to elucidate the effect of FSW parameters on the tensile strength, impact strength and microstructural behaviors of dissimilar welding of the AA7075 T6 and AZ31B Mg alloys. Aluminum and magnesium sheets were successfully joined using FSW and the samples were tested for the mechanical and microstructural properties to determine the optimal welding variables. The welding process was performed using different feed rates, offset values and tool profiles while spindle speed was kept constant. The joining sheets were heated with hot air blowing behind the tool during the FSW process to prevent crack formation due to the residual stress. The tests results showed that the better tensile and impact strengths were obtained with square tool a constant spindle speed of 500 rev/min, a feed rate of 20 mm/min, and a tool offset of 0.2 mm. It was also observed the formation of tunnel because of low melting temperatures and insufficient mixing caused to reduction of area and notch effect in the welded zone.