Tensile and Fatigue Behavior of High Pressure Die Cast AE44 Magnesium Alloy at Elevated Temperatures

Tensile and cyclic behavior of high pressure die cast AE44 magnesium alloy have been studied at room temperature and elevated temperatures up to 350°C. Anelastic behavior has been found in both tensile and cyclic loading at the temperature below 200°C. With increasing temperature, the anelasticity disappears, and tensile and cyclic behaviors become like other engineering materials, such as steels and aluminum alloys, i.e. the total strain contains only elastic strain and plastic strain. A method to determine the yield strength at 0.2% plastic strain (σ_0.2) is proposed. By using the proposed method, the yield strength σ_0.2 is found to be higher than that determined using the traditional method, which is more suitable to the materials that do not exhibit anelasticity. It is believed that the anelasticity is closely related to twinning in Mg alloy, which disappears at elevated temperatures.