Uniaxial ratcheting and low-cycle fatigue failure behaviors of AZ91D magnesium alloy under cyclic tension deformation

Uniaxial ratcheting and low-cycle fatigue failure behaviors of hot-rolled AZ91D magnesium alloy were studied by uniaxial cyclic stress-controlling tension deformation experiments. The effects of stress amplitude, mean stress and stress rate on the uniaxial ratcheting response and fatigue life of the hot-rolled AZ91D magnesium alloy were analyzed. Results show that (1) the ratcheting strain and ratcheting strain rate of the hot-rolled AZ91D magnesium alloy both increase with the increase of stress amplitude or mean stress; (2) increasing stress rate will decrease the ratcheting strain and ratcheting strain rate of the hot-rolled AZ91D magnesium alloy; (3) the increase of stress amplitude and mean stress can both reduce the fatigue life of the hot-rolled AZ91D magnesium alloy, while the fatigue life will be prolonged with the increase of stress rate.

► The effects of stress amplitude, mean stress and stress rate on the ratcheting response and low-cycle fatigue failure of hot-rolled AZ91D magnesium alloy were analyzed.
► The increase of stress amplitude and mean stress will both increase the ratcheting strain (rate) and reduce the fatigue life of the hot-rolled AZ91D magnesium alloy.
► The increase of stress rate will decrease the ratcheting strain (rate) and increase the fatigue life of the hot-rolled AZ91D magnesium alloy.