FRICTION-STIR WELDING AND SURFACE-FRICTION WELDING OF TWIN-ROLL STRIP CAST ZMA611 MG ALLOY

Abstract

Twin-roll strip cast Mg-6Zn-1Mn-1Al (ZMA611) alloy sheet was subjected to friction stir welding (FSW) and surface friction welding (SFW) and their microstructure and mechanical properties were investigated. It shows that stir zones (SZs) of both FSWed and SFWed sheets are dynamically recrystallized, but the grain size of SZ of FSWed sheet is finer than that of SZ of SFWed sheet. Moreover, the structure is inhomogeneous through the thickness in SFWed sheet. Such difference in the microstructures between FSWed and SFWed sheets affect their fracture behaviour and tensile prperties.