Strain-Hardening and Fracture Behavior of Die Cast Magnesium Alloy AM50

Understanding tensile and fracture behaviors of die cast magnesium alloys is of importance for proper design of various emerging automotive applications. In the present study, magnesium alloy AM50 was high pressure die cast into rectangular coupons with section thicknesses of 2, 6, and 10 mm. Effect of section thicknesses on strain-hardening and fracture behaviors of the die cast AM50 was investigated. The results of tensile testing indicate that the tensile properties including yield strength (YS), ultimate tensile strength (UTS), and elongation (Ef) decrease with increasing section thicknesses of die cast AM50. The analysis of true stress versus strain curves shows that the straining hardening rates during the plastic deformation of the alloy increase with decreasing section thicknesses. The observation via SEM fractography illustrates that the fracture behavior of die cast AM50 is influenced by section thicknesses. As the section thickness increases, the fracture of AM50 tends to transit from ductile to brittle mode due to increasing porosity content and coarsening microstructure.