Mechanical properties of thixomolded AZ91D magnesium alloy

Tensile properties of thixomolded AZ91D alloy were studied to investigate the fracture mechanism by the microstructure and decohesion surfaces of tensile specimens which were manufactured at different processing conditions including barrel temperature, shot velocity, mold temperature and screw rotation speed. The results revealed that mechanical properties of thixomolded AZ91D mainly depended on porosity level, the size and volume fraction of primary solid phase and the size of α-Mg and β-Mg17Al12 in liquid phase. The increase in barrel temperature and shot velocity would cause the increase of both strength and ductility, while increasing mold temperature or improving screw rotation speed was coupled by the reduction of tensile properties. The tensile behaviors for different processing parameters were reasonably interpreted through the dependant factors during the deformation.