Strain-rate effects of sand-cast and die-cast magnesium alloys under compressive loading

Abstract

The strain-rate effects of cast magnesium alloys were investigated with uniaxial compression and compressive impact testing. The compressive material response of specimens cut from sand cast AZ91, AE44, and AM60, and high-pressure die-cast AM60 was determined for strain-rates ranging from quasi-static levels to typical rates experienced during crash situations. Several different constitutive material models (Johnson-Cook. Cowper-Symonds, etc.) were used in an attempt to characterize the experimental results. These material models are typically available in commercial finite-element packages and can be used to model the resulting material response of die-cast automotive components produced with these alloys to more complex loading conditions. The resulting deformed microstructures and fracture surfaces of each alloy at different strain-rates were also analyzed.