Investigation of microstructure and mechanical properties of semi-solid state joining of SSM aluminum alloys

In this research, the semi-solid state joining of SSM A356 aluminum alloy was investigated. The butt-joint of SSM A356 was heated by an induction heating coil to create a localized semisolid pool. Then a stirrer was applied into the joint seam in order to mix the weld metal. The accurate controlling of temperature during joining was measured. The effects of stirring rate on physical, macrostructure, microstructure and mechanical properties were studied. Experimental results showed that increase in stirring rates, the surface of the joint was smooth. The weld metal consisted of the globular microstructure and also voids. The density of weld metal zone increased by an appropriate stirring. The best tensile strength was achieved with 1750 rpm, 70 mm/min for 103.4 MPa.