Material flow behavior and mechanical characterization of dissimilar friction stir welded Cu-Mg alloy joints

Abstract

Magnesium alloys are considered to be the lightest material, whereas pure copper is known for better electrical and thermal conductivity finds their applicability especially in automotive and electronic industries. Joining of pure copper and Mg alloy has been studied by many researchers. However, very limited work are available for joining of Cu alloy with Mg Alloy. In the present study, friction stir welding was performed to join Cu-8Zn alloy and Mg AZ31 alloy plates of 3 mm thickness. The process parameters were selected as 1200 rpm rotational speed, 20 mm/min traverse speed, 3° tilt angle, and 0.5 mm tool offset towards copper side. The weld samples were studied for microstructural and mechanical properties. The obtained results by SEM and XRD revealed that there is a complex intercalated microstructure and Mg2Cu intermetallic compounds (IMCs) are present in the stir zone (SZ). Variation in hardness has been observed in the microstructure and maximum hardness of 162.54 HV was found in the SZ due to the presence of Mg2Cu and dynamic recrystallization of grains. The tensile strength of 72 MPa has been attained.