Microstructure and mechanical properties of friction spot welds of dissimilar AA5754 Al and AZ31 Mg alloys

Abstract

In the present study, friction spot welding or refill friction stir spot welding was performed to consolidate dissimilar AA5754 Al and AZ31 Mg alloys. The intermetallic compounds of Al12Mg17 and Al3Mg2 were primarily found in the weld, distributed at the interface between the base materials and in the Al top sheet. The distribution of the intermetallic compounds and the interfacial area between the base materials affect the lap shear strength of the weld. It is concluded that the material flow induced by tool movement plays an important role in both the distribution of the intermetallic compounds and the interfacial area between the base materials.