Formation of Intermetallic Compounds in Dissimilar Friction Spot Weld of Al to Mg Alloys

Abstract

In the present study, friction spot welding has been used for joining dissimilar AA5754 aluminum to AZ31 magnesium alloys. To get more insight into the microstructure, stop-action experimentation was employed. The welding cycle was forced to stop during the dwell time, and subsequently, the weld was quenched by pouring a mixed solution of ice and water to freeze the microstructure. Formation of the liquid phase leading to a formation of brittle intermetallic compound has been studied. Microstructural analyses reveal that formation of intercalated layers and a high density of grain boundaries induced by plastic deformation enhance the formation of eutectic structure during the welding process.